diff --git a/.gitignore b/.gitignore
index 9758937..72b31cd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -55,7 +55,8 @@ coverage.xml
 # Sphinx documentation
 docs/_build/
 .ipynb_checkpoints
-default_sem_eq_weights.rst
+graph_default_sem_eq_weights.rst
+object_default_sem_eq_weights.rst
 
 # PyBuilder
 target/
diff --git a/docs/api/equivalence/pattern/compare/stix2.equivalence.pattern.compare.comparison.rst b/docs/api/equivalence/pattern/compare/stix2.equivalence.pattern.compare.comparison.rst
new file mode 100644
index 0000000..37c6cc0
--- /dev/null
+++ b/docs/api/equivalence/pattern/compare/stix2.equivalence.pattern.compare.comparison.rst
@@ -0,0 +1,5 @@
+comparison
+============================================
+
+.. automodule:: stix2.equivalence.pattern.compare.comparison
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/pattern/compare/stix2.equivalence.pattern.compare.observation.rst b/docs/api/equivalence/pattern/compare/stix2.equivalence.pattern.compare.observation.rst
new file mode 100644
index 0000000..463e11f
--- /dev/null
+++ b/docs/api/equivalence/pattern/compare/stix2.equivalence.pattern.compare.observation.rst
@@ -0,0 +1,5 @@
+observation
+=============================================
+
+.. automodule:: stix2.equivalence.pattern.compare.observation
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/pattern/stix2.equivalence.pattern.compare.rst b/docs/api/equivalence/pattern/stix2.equivalence.pattern.compare.rst
new file mode 100644
index 0000000..3f64bea
--- /dev/null
+++ b/docs/api/equivalence/pattern/stix2.equivalence.pattern.compare.rst
@@ -0,0 +1,5 @@
+compare
+=================================
+
+.. automodule:: stix2.equivalence.pattern.compare
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/pattern/stix2.equivalence.pattern.transform.rst b/docs/api/equivalence/pattern/stix2.equivalence.pattern.transform.rst
new file mode 100644
index 0000000..a26102b
--- /dev/null
+++ b/docs/api/equivalence/pattern/stix2.equivalence.pattern.transform.rst
@@ -0,0 +1,5 @@
+transform
+===================================
+
+.. automodule:: stix2.equivalence.pattern.transform
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.comparison.rst b/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.comparison.rst
new file mode 100644
index 0000000..e2b5d42
--- /dev/null
+++ b/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.comparison.rst
@@ -0,0 +1,5 @@
+comparison
+==============================================
+
+.. automodule:: stix2.equivalence.pattern.transform.comparison
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.observation.rst b/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.observation.rst
new file mode 100644
index 0000000..607bdcf
--- /dev/null
+++ b/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.observation.rst
@@ -0,0 +1,5 @@
+observation
+===============================================
+
+.. automodule:: stix2.equivalence.pattern.transform.observation
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.specials.rst b/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.specials.rst
new file mode 100644
index 0000000..f8191c3
--- /dev/null
+++ b/docs/api/equivalence/pattern/transform/stix2.equivalence.pattern.transform.specials.rst
@@ -0,0 +1,5 @@
+specials
+============================================
+
+.. automodule:: stix2.equivalence.pattern.transform.specials
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/patterns/compare/stix2.equivalence.patterns.compare.comparison.rst b/docs/api/equivalence/patterns/compare/stix2.equivalence.patterns.compare.comparison.rst
deleted file mode 100644
index 8e53da7..0000000
--- a/docs/api/equivalence/patterns/compare/stix2.equivalence.patterns.compare.comparison.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-comparison
-==============
-
-.. automodule:: stix2.equivalence.patterns.compare.comparison
-   :members:
diff --git a/docs/api/equivalence/patterns/compare/stix2.equivalence.patterns.compare.observation.rst b/docs/api/equivalence/patterns/compare/stix2.equivalence.patterns.compare.observation.rst
deleted file mode 100644
index 1abd64e..0000000
--- a/docs/api/equivalence/patterns/compare/stix2.equivalence.patterns.compare.observation.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-observation
-==============
-
-.. automodule:: stix2.equivalence.patterns.compare.observation
-   :members:
diff --git a/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.comparison.rst b/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.comparison.rst
deleted file mode 100644
index 2cf8388..0000000
--- a/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.comparison.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-comparison
-==============
-
-.. automodule:: stix2.equivalence.patterns.transform.comparison
-   :members:
diff --git a/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.observation.rst b/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.observation.rst
deleted file mode 100644
index 1815e7e..0000000
--- a/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.observation.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-observation
-==============
-
-.. automodule:: stix2.equivalence.patterns.transform.observation
-   :members:
diff --git a/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.specials.rst b/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.specials.rst
deleted file mode 100644
index 7930ae2..0000000
--- a/docs/api/equivalence/patterns/transform/stix2.equivalence.patterns.transform.specials.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-specials
-==============
-
-.. automodule:: stix2.equivalence.patterns.transform.specials
-   :members:
diff --git a/docs/api/equivalence/stix2.equivalence.graph.rst b/docs/api/equivalence/stix2.equivalence.graph.rst
new file mode 100644
index 0000000..0cc2922
--- /dev/null
+++ b/docs/api/equivalence/stix2.equivalence.graph.rst
@@ -0,0 +1,5 @@
+graph
+=======================
+
+.. automodule:: stix2.equivalence.graph
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/stix2.equivalence.object.rst b/docs/api/equivalence/stix2.equivalence.object.rst
new file mode 100644
index 0000000..76f5274
--- /dev/null
+++ b/docs/api/equivalence/stix2.equivalence.object.rst
@@ -0,0 +1,5 @@
+object
+========================
+
+.. automodule:: stix2.equivalence.object
+   :members:
\ No newline at end of file
diff --git a/docs/api/equivalence/stix2.equivalence.pattern.rst b/docs/api/equivalence/stix2.equivalence.pattern.rst
new file mode 100644
index 0000000..5246ed2
--- /dev/null
+++ b/docs/api/equivalence/stix2.equivalence.pattern.rst
@@ -0,0 +1,5 @@
+pattern
+==============
+
+.. automodule:: stix2.equivalence.pattern
+   :members:
diff --git a/docs/api/equivalence/stix2.equivalence.patterns.rst b/docs/api/equivalence/stix2.equivalence.patterns.rst
deleted file mode 100644
index 32377f1..0000000
--- a/docs/api/equivalence/stix2.equivalence.patterns.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-patterns
-==============
-
-.. automodule:: stix2.equivalence.patterns
-   :members:
diff --git a/docs/conf.py b/docs/conf.py
index 8b372d5..9723e39 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -8,7 +8,8 @@ from six import class_types
 from sphinx.ext.autodoc import ClassDocumenter
 
 from stix2.base import _STIXBase
-from stix2.environment import WEIGHTS
+from stix2.equivalence.graph import GRAPH_WEIGHTS
+from stix2.equivalence.object import WEIGHTS
 from stix2.version import __version__
 
 sys.path.insert(0, os.path.abspath('..'))
@@ -62,12 +63,19 @@ latex_documents = [
 ]
 
 # Add a formatted version of environment.WEIGHTS
-default_sem_eq_weights = json.dumps(WEIGHTS, indent=4, default=lambda o: o.__name__)
-default_sem_eq_weights = default_sem_eq_weights.replace('\n', '\n    ')
-default_sem_eq_weights = default_sem_eq_weights.replace('               "', '               ')
-default_sem_eq_weights = default_sem_eq_weights.replace('"\n', '\n')
-with open('default_sem_eq_weights.rst', 'w') as f:
-    f.write(".. code-block:: py\n\n   {}\n\n".format(default_sem_eq_weights))
+object_default_sem_eq_weights = json.dumps(WEIGHTS, indent=4, default=lambda o: o.__name__)
+object_default_sem_eq_weights = object_default_sem_eq_weights.replace('\n', '\n    ')
+object_default_sem_eq_weights = object_default_sem_eq_weights.replace('               "', '               ')
+object_default_sem_eq_weights = object_default_sem_eq_weights.replace('"\n', '\n')
+with open('object_default_sem_eq_weights.rst', 'w') as f:
+    f.write(".. code-block:: python\n\n   {}\n\n".format(object_default_sem_eq_weights))
+
+graph_default_sem_eq_weights = json.dumps(GRAPH_WEIGHTS, indent=4, default=lambda o: o.__name__)
+graph_default_sem_eq_weights = graph_default_sem_eq_weights.replace('\n', '\n    ')
+graph_default_sem_eq_weights = graph_default_sem_eq_weights.replace('               "', '               ')
+graph_default_sem_eq_weights = graph_default_sem_eq_weights.replace('"\n', '\n')
+with open('graph_default_sem_eq_weights.rst', 'w') as f:
+    f.write(".. code-block:: python\n\n   {}\n\n".format(graph_default_sem_eq_weights))
 
 
 def get_property_type(prop):
diff --git a/docs/guide/equivalence.ipynb b/docs/guide/equivalence.ipynb
index c0b9331..8393495 100644
--- a/docs/guide/equivalence.ipynb
+++ b/docs/guide/equivalence.ipynb
@@ -2165,15 +2165,17 @@
     "The weights dictionary should contain both the weight and the comparison function for each property. You may use the default weights and functions, or provide your own.\n",
     "\n",
     "##### Existing comparison functions\n",
-    "For reference, here is a list of the comparison functions already built in the codebase (found in [stix2/environment.py](../api/stix2.environment.rst#stix2.environment.Environment)):\n",
+    "For reference, here is a list of the comparison functions already built in the codebase (found in [stix2/equivalence/object](../api/equivalence/stix2.equivalence.object.rst#module-stix2.equivalence.object)):\n",
     "\n",
-    " - [custom_pattern_based](../api/stix2.environment.rst#stix2.environment.custom_pattern_based)\n",
-    " - [exact_match](../api/stix2.environment.rst#stix2.environment.exact_match)\n",
-    " - [partial_external_reference_based](../api/stix2.environment.rst#stix2.environment.partial_external_reference_based)\n",
-    " - [partial_list_based](../api/stix2.environment.rst#stix2.environment.partial_list_based)\n",
-    " - [partial_location_distance](../api/stix2.environment.rst#stix2.environment.partial_location_distance)\n",
-    " - [partial_string_based](../api/stix2.environment.rst#stix2.environment.partial_string_based)\n",
-    " - [partial_timestamp_based](../api/stix2.environment.rst#stix2.environment.partial_timestamp_based)\n",
+    " - [custom_pattern_based](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.custom_pattern_based)\n",
+    " - [exact_match](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.exact_match)\n",
+    " - [list_reference_check](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.list_reference_check)\n",
+    " - [partial_external_reference_based](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.partial_external_reference_based)\n",
+    " - [partial_list_based](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.partial_list_based)\n",
+    " - [partial_location_distance](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.partial_location_distance)\n",
+    " - [partial_string_based](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.partial_string_based)\n",
+    " - [partial_timestamp_based](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.partial_timestamp_based)\n",
+    " - [reference_check](../api/equivalence/stix2.equivalence.object.rst#stix2.equivalence.object.reference_check)\n",
     "\n",
     "For instance, if we wanted to compare two of the `ThreatActor`s from before, but use our own weights, then we could do the following:"
    ]
diff --git a/requirements.txt b/requirements.txt
index 8a5e4a2..fa1773a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,6 @@
 bumpversion
 ipython
+nbconvert<6
 nbsphinx==0.4.3
 pre-commit
 pygments<3,>=2.4.1
diff --git a/stix2/datastore/__init__.py b/stix2/datastore/__init__.py
index 57cb513..1ff0769 100644
--- a/stix2/datastore/__init__.py
+++ b/stix2/datastore/__init__.py
@@ -481,14 +481,14 @@ class CompositeDataSource(DataSource):
             if data:
                 all_data.append(data)
 
-        # remove duplicate versions
-        if len(all_data) > 0:
-            all_data = deduplicate(all_data)
-        else:
-            return None
+        # Search for latest version
+        stix_obj = latest_ver = None
+        for obj in all_data:
+            ver = obj.get("modified") or obj.get("created")
 
-        # reduce to most recent version
-        stix_obj = sorted(all_data, key=lambda k: k['modified'], reverse=True)[0]
+            if stix_obj is None or ver is None or ver > latest_ver:
+                stix_obj = obj
+                latest_ver = ver
 
         return stix_obj
 
diff --git a/stix2/environment.py b/stix2/environment.py
index 0a6bdb2..4dc6ff0 100644
--- a/stix2/environment.py
+++ b/stix2/environment.py
@@ -1,13 +1,18 @@
 """Python STIX2 Environment API."""
 import copy
-import logging
-import time
 
 from .datastore import CompositeDataSource, DataStoreMixin
+from .equivalence.graph import graphically_equivalent
+from .equivalence.object import (  # noqa: F401
+    WEIGHTS, check_property_present, custom_pattern_based, exact_match,
+    list_reference_check, partial_external_reference_based, partial_list_based,
+    partial_location_distance, partial_string_based, partial_timestamp_based,
+    reference_check, semantically_equivalent,
+)
 from .parsing import parse as _parse
-from .utils import STIXdatetime, parse_into_datetime
 
-logger = logging.getLogger(__name__)
+# TODO: Remove all unused imports that now belong to the equivalence module in the next major release.
+# Kept for backwards compatibility.
 
 
 class ObjectFactory(object):
@@ -193,7 +198,7 @@ class Environment(DataStoreMixin):
 
     @staticmethod
     def semantically_equivalent(obj1, obj2, prop_scores={}, **weight_dict):
-        """This method is meant to verify if two objects of the same type are
+        """This method verifies if two objects of the same type are
         semantically equivalent.
 
         Args:
@@ -208,315 +213,58 @@ class Environment(DataStoreMixin):
             float: A number between 0.0 and 100.0 as a measurement of equivalence.
 
         Warning:
-            Course of Action, Intrusion-Set, Observed-Data, Report are not supported
-            by this implementation. Indicator pattern check is also limited.
+            Object types need to have property weights defined for the equivalence process.
+            Otherwise, those objects will not influence the final score. The WEIGHTS
+            dictionary under `stix2.equivalence.object` can give you an idea on how to add
+            new entries and pass them via the `weight_dict` argument. Similarly, the values
+            or methods can be fine tuned for a particular use case.
 
         Note:
-            Default weights_dict:
+            Default weight_dict:
 
-            .. include:: ../default_sem_eq_weights.rst
+            .. include:: ../object_default_sem_eq_weights.rst
 
         Note:
-            This implementation follows the Committee Note on semantic equivalence.
+            This implementation follows the Semantic Equivalence Committee Note.
             see `the Committee Note <link here>`__.
 
         """
-        weights = WEIGHTS.copy()
+        return semantically_equivalent(obj1, obj2, prop_scores, **weight_dict)
 
-        if weight_dict:
-            weights.update(weight_dict)
+    @staticmethod
+    def graphically_equivalent(ds1, ds2, prop_scores={}, **weight_dict):
+        """This method verifies if two graphs are semantically equivalent.
+        Each DataStore can contain a connected or disconnected graph and the
+        final result is weighted over the amount of objects we managed to compare.
+        This approach builds on top of the object-based semantic equivalence process
+        and each comparison can return a value between 0 and 100.
 
-        type1, type2 = obj1["type"], obj2["type"]
-        ignore_spec_version = weights["_internal"]["ignore_spec_version"]
+        Args:
+            ds1: A DataStore object instance representing your graph
+            ds2: A DataStore object instance representing your graph
+            prop_scores: A dictionary that can hold individual property scores,
+                weights, contributing score, matching score and sum of weights.
+            weight_dict: A dictionary that can be used to override settings
+                in the semantic equivalence process
 
-        if type1 != type2:
-            raise ValueError('The objects to compare must be of the same type!')
+        Returns:
+            float: A number between 0.0 and 100.0 as a measurement of equivalence.
 
-        if ignore_spec_version is False and obj1.get("spec_version", "2.0") != obj2.get("spec_version", "2.0"):
-            raise ValueError('The objects to compare must be of the same spec version!')
+        Warning:
+            Object types need to have property weights defined for the equivalence process.
+            Otherwise, those objects will not influence the final score. The WEIGHTS
+            dictionary under `stix2.equivalence.graph` can give you an idea on how to add
+            new entries and pass them via the `weight_dict` argument. Similarly, the values
+            or methods can be fine tuned for a particular use case.
 
-        try:
-            weights[type1]
-        except KeyError:
-            logger.warning("'%s' type has no 'weights' dict specified & thus no semantic equivalence method to call!", type1)
-            sum_weights = matching_score = 0
-        else:
-            try:
-                method = weights[type1]["method"]
-            except KeyError:
-                logger.debug("Starting semantic equivalence process between: '%s' and '%s'", obj1["id"], obj2["id"])
-                matching_score = 0.0
-                sum_weights = 0.0
+        Note:
+            Default weight_dict:
 
-                for prop in weights[type1]:
-                    if check_property_present(prop, obj1, obj2) or prop == "longitude_latitude":
-                        w = weights[type1][prop][0]
-                        comp_funct = weights[type1][prop][1]
+            .. include:: ../graph_default_sem_eq_weights.rst
 
-                        if comp_funct == partial_timestamp_based:
-                            contributing_score = w * comp_funct(obj1[prop], obj2[prop], weights[type1]["tdelta"])
-                        elif comp_funct == partial_location_distance:
-                            threshold = weights[type1]["threshold"]
-                            contributing_score = w * comp_funct(obj1["latitude"], obj1["longitude"], obj2["latitude"], obj2["longitude"], threshold)
-                        else:
-                            contributing_score = w * comp_funct(obj1[prop], obj2[prop])
+        Note:
+            This implementation follows the Semantic Equivalence Committee Note.
+            see `the Committee Note <link here>`__.
 
-                        sum_weights += w
-                        matching_score += contributing_score
-
-                        prop_scores[prop] = {
-                            "weight": w,
-                            "contributing_score": contributing_score,
-                        }
-                        logger.debug("'%s' check -- weight: %s, contributing score: %s", prop, w, contributing_score)
-
-                prop_scores["matching_score"] = matching_score
-                prop_scores["sum_weights"] = sum_weights
-                logger.debug("Matching Score: %s, Sum of Weights: %s", matching_score, sum_weights)
-            else:
-                logger.debug("Starting semantic equivalence process between: '%s' and '%s'", obj1["id"], obj2["id"])
-                try:
-                    matching_score, sum_weights = method(obj1, obj2, prop_scores, **weights[type1])
-                except TypeError:
-                    # method doesn't support detailed output with prop_scores
-                    matching_score, sum_weights = method(obj1, obj2, **weights[type1])
-                logger.debug("Matching Score: %s, Sum of Weights: %s", matching_score, sum_weights)
-
-        if sum_weights <= 0:
-            return 0
-        equivalence_score = (matching_score / sum_weights) * 100.0
-        return equivalence_score
-
-
-def check_property_present(prop, obj1, obj2):
-    """Helper method checks if a property is present on both objects."""
-    if prop in obj1 and prop in obj2:
-        return True
-    return False
-
-
-def partial_timestamp_based(t1, t2, tdelta):
-    """Performs a timestamp-based matching via checking how close one timestamp is to another.
-
-    Args:
-        t1: A datetime string or STIXdatetime object.
-        t2: A datetime string or STIXdatetime object.
-        tdelta (float): A given time delta. This number is multiplied by 86400 (1 day) to
-            extend or shrink your time change tolerance.
-
-    Returns:
-        float: Number between 0.0 and 1.0 depending on match criteria.
-
-    """
-    if not isinstance(t1, STIXdatetime):
-        t1 = parse_into_datetime(t1)
-    if not isinstance(t2, STIXdatetime):
-        t2 = parse_into_datetime(t2)
-    t1, t2 = time.mktime(t1.timetuple()), time.mktime(t2.timetuple())
-    result = 1 - min(abs(t1 - t2) / (86400 * tdelta), 1)
-    logger.debug("--\t\tpartial_timestamp_based '%s' '%s' tdelta: '%s'\tresult: '%s'", t1, t2, tdelta, result)
-    return result
-
-
-def partial_list_based(l1, l2):
-    """Performs a partial list matching via finding the intersection between common values.
-
-    Args:
-        l1: A list of values.
-        l2: A list of values.
-
-    Returns:
-        float: 1.0 if the value matches exactly, 0.0 otherwise.
-
-    """
-    l1_set, l2_set = set(l1), set(l2)
-    result = len(l1_set.intersection(l2_set)) / max(len(l1), len(l2))
-    logger.debug("--\t\tpartial_list_based '%s' '%s'\tresult: '%s'", l1, l2, result)
-    return result
-
-
-def exact_match(val1, val2):
-    """Performs an exact value match based on two values
-
-    Args:
-        val1: A value suitable for an equality test.
-        val2: A value suitable for an equality test.
-
-    Returns:
-        float: 1.0 if the value matches exactly, 0.0 otherwise.
-
-    """
-    result = 0.0
-    if val1 == val2:
-        result = 1.0
-    logger.debug("--\t\texact_match '%s' '%s'\tresult: '%s'", val1, val2, result)
-    return result
-
-
-def partial_string_based(str1, str2):
-    """Performs a partial string match using the Jaro-Winkler distance algorithm.
-
-    Args:
-        str1: A string value to check.
-        str2: A string value to check.
-
-    Returns:
-        float: Number between 0.0 and 1.0 depending on match criteria.
-
-    """
-    from rapidfuzz import fuzz
-    result = fuzz.token_sort_ratio(str1, str2)
-    logger.debug("--\t\tpartial_string_based '%s' '%s'\tresult: '%s'", str1, str2, result)
-    return result / 100.0
-
-
-def custom_pattern_based(pattern1, pattern2):
-    """Performs a matching on Indicator Patterns.
-
-    Args:
-        pattern1: An Indicator pattern
-        pattern2: An Indicator pattern
-
-    Returns:
-        float: Number between 0.0 and 1.0 depending on match criteria.
-
-    """
-    logger.warning("Indicator pattern equivalence is not fully defined; will default to zero if not completely identical")
-    return exact_match(pattern1, pattern2)  # TODO: Implement pattern based equivalence
-
-
-def partial_external_reference_based(refs1, refs2):
-    """Performs a matching on External References.
-
-    Args:
-        refs1: A list of external references.
-        refs2: A list of external references.
-
-    Returns:
-        float: Number between 0.0 and 1.0 depending on matches.
-
-    """
-    allowed = set(("veris", "cve", "capec", "mitre-attack"))
-    matches = 0
-
-    if len(refs1) >= len(refs2):
-        l1 = refs1
-        l2 = refs2
-    else:
-        l1 = refs2
-        l2 = refs1
-
-    for ext_ref1 in l1:
-        for ext_ref2 in l2:
-            sn_match = False
-            ei_match = False
-            url_match = False
-            source_name = None
-
-            if check_property_present("source_name", ext_ref1, ext_ref2):
-                if ext_ref1["source_name"] == ext_ref2["source_name"]:
-                    source_name = ext_ref1["source_name"]
-                    sn_match = True
-            if check_property_present("external_id", ext_ref1, ext_ref2):
-                if ext_ref1["external_id"] == ext_ref2["external_id"]:
-                    ei_match = True
-            if check_property_present("url", ext_ref1, ext_ref2):
-                if ext_ref1["url"] == ext_ref2["url"]:
-                    url_match = True
-
-            # Special case: if source_name is a STIX defined name and either
-            # external_id or url match then its a perfect match and other entries
-            # can be ignored.
-            if sn_match and (ei_match or url_match) and source_name in allowed:
-                result = 1.0
-                logger.debug(
-                    "--\t\tpartial_external_reference_based '%s' '%s'\tresult: '%s'",
-                    refs1, refs2, result,
-                )
-                return result
-
-            # Regular check. If the source_name (not STIX-defined) or external_id or
-            # url matches then we consider the entry a match.
-            if (sn_match or ei_match or url_match) and source_name not in allowed:
-                matches += 1
-
-    result = matches / max(len(refs1), len(refs2))
-    logger.debug(
-        "--\t\tpartial_external_reference_based '%s' '%s'\tresult: '%s'",
-        refs1, refs2, result,
-    )
-    return result
-
-
-def partial_location_distance(lat1, long1, lat2, long2, threshold):
-    """Given two coordinates perform a matching based on its distance using the Haversine Formula.
-
-    Args:
-        lat1: Latitude value for first coordinate point.
-        lat2: Latitude value for second coordinate point.
-        long1: Longitude value for first coordinate point.
-        long2: Longitude value for second coordinate point.
-        threshold (float): A kilometer measurement for the threshold distance between these two points.
-
-    Returns:
-        float: Number between 0.0 and 1.0 depending on match.
-
-    """
-    from haversine import Unit, haversine
-    distance = haversine((lat1, long1), (lat2, long2), unit=Unit.KILOMETERS)
-    result = 1 - (distance / threshold)
-    logger.debug(
-        "--\t\tpartial_location_distance '%s' '%s' threshold: '%s'\tresult: '%s'",
-        (lat1, long1), (lat2, long2), threshold, result,
-    )
-    return result
-
-
-# default weights used for the semantic equivalence process
-WEIGHTS = {
-    "attack-pattern": {
-        "name": (30, partial_string_based),
-        "external_references": (70, partial_external_reference_based),
-    },
-    "campaign": {
-        "name": (60, partial_string_based),
-        "aliases": (40, partial_list_based),
-    },
-    "identity": {
-        "name": (60, partial_string_based),
-        "identity_class": (20, exact_match),
-        "sectors": (20, partial_list_based),
-    },
-    "indicator": {
-        "indicator_types": (15, partial_list_based),
-        "pattern": (80, custom_pattern_based),
-        "valid_from": (5, partial_timestamp_based),
-        "tdelta": 1,  # One day interval
-    },
-    "location": {
-        "longitude_latitude": (34, partial_location_distance),
-        "region": (33, exact_match),
-        "country": (33, exact_match),
-        "threshold": 1000.0,
-    },
-    "malware": {
-        "malware_types": (20, partial_list_based),
-        "name": (80, partial_string_based),
-    },
-    "threat-actor": {
-        "name": (60, partial_string_based),
-        "threat_actor_types": (20, partial_list_based),
-        "aliases": (20, partial_list_based),
-    },
-    "tool": {
-        "tool_types": (20, partial_list_based),
-        "name": (80, partial_string_based),
-    },
-    "vulnerability": {
-        "name": (30, partial_string_based),
-        "external_references": (70, partial_external_reference_based),
-    },
-    "_internal": {
-        "ignore_spec_version": False,
-    },
-}  #: :autodoc-skip:
+        """
+        return graphically_equivalent(ds1, ds2, prop_scores, **weight_dict)
diff --git a/stix2/equivalence/__init__.py b/stix2/equivalence/__init__.py
index c67e649..f175024 100644
--- a/stix2/equivalence/__init__.py
+++ b/stix2/equivalence/__init__.py
@@ -3,7 +3,9 @@
 .. autosummary::
    :toctree: equivalence
 
-   patterns
+   pattern
+   graph
+   object
 
 |
 """
diff --git a/stix2/equivalence/graph/__init__.py b/stix2/equivalence/graph/__init__.py
new file mode 100644
index 0000000..680f42f
--- /dev/null
+++ b/stix2/equivalence/graph/__init__.py
@@ -0,0 +1,137 @@
+"""Python APIs for STIX 2 Graph-based Semantic Equivalence."""
+import logging
+
+from ..object import (
+    WEIGHTS, exact_match, list_reference_check, partial_string_based,
+    partial_timestamp_based, reference_check, semantically_equivalent,
+)
+
+logger = logging.getLogger(__name__)
+
+
+def graphically_equivalent(ds1, ds2, prop_scores={}, **weight_dict):
+    """This method verifies if two graphs are semantically equivalent.
+    Each DataStore can contain a connected or disconnected graph and the
+    final result is weighted over the amount of objects we managed to compare.
+    This approach builds on top of the object-based semantic equivalence process
+    and each comparison can return a value between 0 and 100.
+
+    Args:
+        ds1: A DataStore object instance representing your graph
+        ds2: A DataStore object instance representing your graph
+        prop_scores: A dictionary that can hold individual property scores,
+            weights, contributing score, matching score and sum of weights.
+        weight_dict: A dictionary that can be used to override settings
+            in the semantic equivalence process
+
+    Returns:
+        float: A number between 0.0 and 100.0 as a measurement of equivalence.
+
+    Warning:
+        Object types need to have property weights defined for the equivalence process.
+        Otherwise, those objects will not influence the final score. The WEIGHTS
+        dictionary under `stix2.equivalence.graph` can give you an idea on how to add
+        new entries and pass them via the `weight_dict` argument. Similarly, the values
+        or methods can be fine tuned for a particular use case.
+
+    Note:
+        Default weights_dict:
+
+        .. include:: ../../graph_default_sem_eq_weights.rst
+
+    Note:
+        This implementation follows the Semantic Equivalence Committee Note.
+        see `the Committee Note <link here>`__.
+
+    """
+    weights = GRAPH_WEIGHTS.copy()
+
+    if weight_dict:
+        weights.update(weight_dict)
+
+    results = {}
+    depth = weights["_internal"]["max_depth"]
+
+    graph1 = ds1.query([])
+    graph2 = ds2.query([])
+
+    graph1.sort(key=lambda x: x["type"])
+    graph2.sort(key=lambda x: x["type"])
+
+    if len(graph1) < len(graph2):
+        weights["_internal"]["ds1"] = ds1
+        weights["_internal"]["ds2"] = ds2
+        g1 = graph1
+        g2 = graph2
+    else:
+        weights["_internal"]["ds1"] = ds2
+        weights["_internal"]["ds2"] = ds1
+        g1 = graph2
+        g2 = graph1
+
+    for object1 in g1:
+        for object2 in g2:
+            if object1["type"] == object2["type"] and object1["type"] in weights:
+                iprop_score = {}
+                result = semantically_equivalent(object1, object2, iprop_score, **weights)
+                objects1_id = object1["id"]
+                weights["_internal"]["max_depth"] = depth
+
+                if objects1_id not in results:
+                    results[objects1_id] = {"matched": object2["id"], "prop_score": iprop_score, "value": result}
+                elif result > results[objects1_id]["value"]:
+                    results[objects1_id] = {"matched": object2["id"], "prop_score": iprop_score, "value": result}
+
+    equivalence_score = 0
+    matching_score = sum(x["value"] for x in results.values())
+    sum_weights = len(results) * 100.0
+    if sum_weights > 0:
+        equivalence_score = (matching_score / sum_weights) * 100
+    prop_scores["matching_score"] = matching_score
+    prop_scores["sum_weights"] = sum_weights
+    prop_scores["summary"] = results
+
+    logger.debug(
+        "DONE\t\tSUM_WEIGHT: %.2f\tMATCHING_SCORE: %.2f\t SCORE: %.2f",
+        sum_weights,
+        matching_score,
+        equivalence_score,
+    )
+    return equivalence_score
+
+
+# default weights used for the graph semantic equivalence process
+GRAPH_WEIGHTS = WEIGHTS.copy()
+GRAPH_WEIGHTS.update({
+    "grouping": {
+        "name": (20, partial_string_based),
+        "context": (20, partial_string_based),
+        "object_refs": (60, list_reference_check),
+    },
+    "relationship": {
+        "relationship_type": (20, exact_match),
+        "source_ref": (40, reference_check),
+        "target_ref": (40, reference_check),
+    },
+    "report": {
+        "name": (30, partial_string_based),
+        "published": (10, partial_timestamp_based),
+        "object_refs": (60, list_reference_check),
+        "tdelta": 1,  # One day interval
+    },
+    "sighting": {
+        "first_seen": (5, partial_timestamp_based),
+        "last_seen": (5, partial_timestamp_based),
+        "sighting_of_ref": (40, reference_check),
+        "observed_data_refs": (20, list_reference_check),
+        "where_sighted_refs": (20, list_reference_check),
+        "summary": (10, exact_match),
+    },
+    "_internal": {
+        "ignore_spec_version": False,
+        "versioning_checks": False,
+        "ds1": None,
+        "ds2": None,
+        "max_depth": 1,
+    },
+})  # :autodoc-skip:
diff --git a/stix2/equivalence/object/__init__.py b/stix2/equivalence/object/__init__.py
new file mode 100644
index 0000000..8333ceb
--- /dev/null
+++ b/stix2/equivalence/object/__init__.py
@@ -0,0 +1,452 @@
+"""Python APIs for STIX 2 Object-based Semantic Equivalence."""
+import logging
+import time
+
+from ...datastore import Filter
+from ...utils import STIXdatetime, parse_into_datetime
+
+logger = logging.getLogger(__name__)
+
+
+def semantically_equivalent(obj1, obj2, prop_scores={}, **weight_dict):
+    """This method verifies if two objects of the same type are
+    semantically equivalent.
+
+    Args:
+        obj1: A stix2 object instance
+        obj2: A stix2 object instance
+        prop_scores: A dictionary that can hold individual property scores,
+            weights, contributing score, matching score and sum of weights.
+        weight_dict: A dictionary that can be used to override settings
+            in the semantic equivalence process
+
+    Returns:
+        float: A number between 0.0 and 100.0 as a measurement of equivalence.
+
+    Warning:
+        Object types need to have property weights defined for the equivalence process.
+        Otherwise, those objects will not influence the final score. The WEIGHTS
+        dictionary under `stix2.equivalence.object` can give you an idea on how to add
+        new entries and pass them via the `weight_dict` argument. Similarly, the values
+        or methods can be fine tuned for a particular use case.
+
+    Note:
+        Default weights_dict:
+
+        .. include:: ../../object_default_sem_eq_weights.rst
+
+    Note:
+        This implementation follows the Semantic Equivalence Committee Note.
+        see `the Committee Note <link here>`__.
+
+    """
+    weights = WEIGHTS.copy()
+
+    if weight_dict:
+        weights.update(weight_dict)
+
+    type1, type2 = obj1["type"], obj2["type"]
+    ignore_spec_version = weights["_internal"]["ignore_spec_version"]
+
+    if type1 != type2:
+        raise ValueError('The objects to compare must be of the same type!')
+
+    if ignore_spec_version is False and obj1.get("spec_version", "2.0") != obj2.get("spec_version", "2.0"):
+        raise ValueError('The objects to compare must be of the same spec version!')
+
+    try:
+        weights[type1]
+    except KeyError:
+        logger.warning("'%s' type has no 'weights' dict specified & thus no semantic equivalence method to call!", type1)
+        sum_weights = matching_score = 0
+    else:
+        try:
+            method = weights[type1]["method"]
+        except KeyError:
+            logger.debug("Starting semantic equivalence process between: '%s' and '%s'", obj1["id"], obj2["id"])
+            matching_score = 0.0
+            sum_weights = 0.0
+
+            for prop in weights[type1]:
+                if check_property_present(prop, obj1, obj2) or prop == "longitude_latitude":
+                    w = weights[type1][prop][0]
+                    comp_funct = weights[type1][prop][1]
+
+                    if comp_funct == partial_timestamp_based:
+                        contributing_score = w * comp_funct(obj1[prop], obj2[prop], weights[type1]["tdelta"])
+                    elif comp_funct == partial_location_distance:
+                        threshold = weights[type1]["threshold"]
+                        contributing_score = w * comp_funct(obj1["latitude"], obj1["longitude"], obj2["latitude"], obj2["longitude"], threshold)
+                    elif comp_funct == reference_check or comp_funct == list_reference_check:
+                        max_depth = weights["_internal"]["max_depth"]
+                        if max_depth < 0:
+                            continue  # prevent excessive recursion
+                        else:
+                            weights["_internal"]["max_depth"] -= 1
+                        ds1, ds2 = weights["_internal"]["ds1"], weights["_internal"]["ds2"]
+                        contributing_score = w * comp_funct(obj1[prop], obj2[prop], ds1, ds2, **weights)
+                    else:
+                        contributing_score = w * comp_funct(obj1[prop], obj2[prop])
+
+                    sum_weights += w
+                    matching_score += contributing_score
+
+                    prop_scores[prop] = {
+                        "weight": w,
+                        "contributing_score": contributing_score,
+                    }
+                    logger.debug("'%s' check -- weight: %s, contributing score: %s", prop, w, contributing_score)
+
+            prop_scores["matching_score"] = matching_score
+            prop_scores["sum_weights"] = sum_weights
+            logger.debug("Matching Score: %s, Sum of Weights: %s", matching_score, sum_weights)
+        else:
+            logger.debug("Starting semantic equivalence process between: '%s' and '%s'", obj1["id"], obj2["id"])
+            try:
+                matching_score, sum_weights = method(obj1, obj2, prop_scores, **weights[type1])
+            except TypeError:
+                # method doesn't support detailed output with prop_scores
+                matching_score, sum_weights = method(obj1, obj2, **weights[type1])
+            logger.debug("Matching Score: %s, Sum of Weights: %s", matching_score, sum_weights)
+
+    if sum_weights <= 0:
+        return 0
+    equivalence_score = (matching_score / sum_weights) * 100.0
+    return equivalence_score
+
+
+def check_property_present(prop, obj1, obj2):
+    """Helper method checks if a property is present on both objects."""
+    if prop in obj1 and prop in obj2:
+        return True
+    return False
+
+
+def partial_timestamp_based(t1, t2, tdelta):
+    """Performs a timestamp-based matching via checking how close one timestamp is to another.
+
+    Args:
+        t1: A datetime string or STIXdatetime object.
+        t2: A datetime string or STIXdatetime object.
+        tdelta (float): A given time delta. This number is multiplied by 86400 (1 day) to
+            extend or shrink your time change tolerance.
+
+    Returns:
+        float: Number between 0.0 and 1.0 depending on match criteria.
+
+    """
+    if not isinstance(t1, STIXdatetime):
+        t1 = parse_into_datetime(t1)
+    if not isinstance(t2, STIXdatetime):
+        t2 = parse_into_datetime(t2)
+    t1, t2 = time.mktime(t1.timetuple()), time.mktime(t2.timetuple())
+    result = 1 - min(abs(t1 - t2) / (86400 * tdelta), 1)
+    logger.debug("--\t\tpartial_timestamp_based '%s' '%s' tdelta: '%s'\tresult: '%s'", t1, t2, tdelta, result)
+    return result
+
+
+def partial_list_based(l1, l2):
+    """Performs a partial list matching via finding the intersection between common values.
+
+    Args:
+        l1: A list of values.
+        l2: A list of values.
+
+    Returns:
+        float: 1.0 if the value matches exactly, 0.0 otherwise.
+
+    """
+    l1_set, l2_set = set(l1), set(l2)
+    result = len(l1_set.intersection(l2_set)) / max(len(l1_set), len(l2_set))
+    logger.debug("--\t\tpartial_list_based '%s' '%s'\tresult: '%s'", l1, l2, result)
+    return result
+
+
+def exact_match(val1, val2):
+    """Performs an exact value match based on two values
+
+    Args:
+        val1: A value suitable for an equality test.
+        val2: A value suitable for an equality test.
+
+    Returns:
+        float: 1.0 if the value matches exactly, 0.0 otherwise.
+
+    """
+    result = 0.0
+    if val1 == val2:
+        result = 1.0
+    logger.debug("--\t\texact_match '%s' '%s'\tresult: '%s'", val1, val2, result)
+    return result
+
+
+def partial_string_based(str1, str2):
+    """Performs a partial string match using the Jaro-Winkler distance algorithm.
+
+    Args:
+        str1: A string value to check.
+        str2: A string value to check.
+
+    Returns:
+        float: Number between 0.0 and 1.0 depending on match criteria.
+
+    """
+    from rapidfuzz import fuzz
+    result = fuzz.token_sort_ratio(str1, str2)
+    logger.debug("--\t\tpartial_string_based '%s' '%s'\tresult: '%s'", str1, str2, result)
+    return result / 100.0
+
+
+def custom_pattern_based(pattern1, pattern2):
+    """Performs a matching on Indicator Patterns.
+
+    Args:
+        pattern1: An Indicator pattern
+        pattern2: An Indicator pattern
+
+    Returns:
+        float: Number between 0.0 and 1.0 depending on match criteria.
+
+    """
+    logger.warning("Indicator pattern equivalence is not fully defined; will default to zero if not completely identical")
+    return exact_match(pattern1, pattern2)  # TODO: Implement pattern based equivalence
+
+
+def partial_external_reference_based(refs1, refs2):
+    """Performs a matching on External References.
+
+    Args:
+        refs1: A list of external references.
+        refs2: A list of external references.
+
+    Returns:
+        float: Number between 0.0 and 1.0 depending on matches.
+
+    """
+    allowed = {"veris", "cve", "capec", "mitre-attack"}
+    matches = 0
+
+    if len(refs1) >= len(refs2):
+        l1 = refs1
+        l2 = refs2
+    else:
+        l1 = refs2
+        l2 = refs1
+
+    for ext_ref1 in l1:
+        for ext_ref2 in l2:
+            sn_match = False
+            ei_match = False
+            url_match = False
+            source_name = None
+
+            if check_property_present("source_name", ext_ref1, ext_ref2):
+                if ext_ref1["source_name"] == ext_ref2["source_name"]:
+                    source_name = ext_ref1["source_name"]
+                    sn_match = True
+            if check_property_present("external_id", ext_ref1, ext_ref2):
+                if ext_ref1["external_id"] == ext_ref2["external_id"]:
+                    ei_match = True
+            if check_property_present("url", ext_ref1, ext_ref2):
+                if ext_ref1["url"] == ext_ref2["url"]:
+                    url_match = True
+
+            # Special case: if source_name is a STIX defined name and either
+            # external_id or url match then its a perfect match and other entries
+            # can be ignored.
+            if sn_match and (ei_match or url_match) and source_name in allowed:
+                result = 1.0
+                logger.debug(
+                    "--\t\tpartial_external_reference_based '%s' '%s'\tresult: '%s'",
+                    refs1, refs2, result,
+                )
+                return result
+
+            # Regular check. If the source_name (not STIX-defined) or external_id or
+            # url matches then we consider the entry a match.
+            if (sn_match or ei_match or url_match) and source_name not in allowed:
+                matches += 1
+
+    result = matches / max(len(refs1), len(refs2))
+    logger.debug(
+        "--\t\tpartial_external_reference_based '%s' '%s'\tresult: '%s'",
+        refs1, refs2, result,
+    )
+    return result
+
+
+def partial_location_distance(lat1, long1, lat2, long2, threshold):
+    """Given two coordinates perform a matching based on its distance using the Haversine Formula.
+
+    Args:
+        lat1: Latitude value for first coordinate point.
+        lat2: Latitude value for second coordinate point.
+        long1: Longitude value for first coordinate point.
+        long2: Longitude value for second coordinate point.
+        threshold (float): A kilometer measurement for the threshold distance between these two points.
+
+    Returns:
+        float: Number between 0.0 and 1.0 depending on match.
+
+    """
+    from haversine import Unit, haversine
+    distance = haversine((lat1, long1), (lat2, long2), unit=Unit.KILOMETERS)
+    result = 1 - (distance / threshold)
+    logger.debug(
+        "--\t\tpartial_location_distance '%s' '%s' threshold: '%s'\tresult: '%s'",
+        (lat1, long1), (lat2, long2), threshold, result,
+    )
+    return result
+
+
+def _versioned_checks(ref1, ref2, ds1, ds2, **weights):
+    """Checks multiple object versions if present in graph.
+    Maximizes for the semantic equivalence score of a particular version."""
+    results = {}
+    objects1 = ds1.query([Filter("id", "=", ref1)])
+    objects2 = ds2.query([Filter("id", "=", ref2)])
+
+    if len(objects1) > 0 and len(objects2) > 0:
+        for o1 in objects1:
+            for o2 in objects2:
+                result = semantically_equivalent(o1, o2, **weights)
+                if ref1 not in results:
+                    results[ref1] = {"matched": ref2, "value": result}
+                elif result > results[ref1]["value"]:
+                    results[ref1] = {"matched": ref2, "value": result}
+    result = results.get(ref1, {}).get("value", 0.0)
+    logger.debug(
+        "--\t\t_versioned_checks '%s' '%s'\tresult: '%s'",
+        ref1, ref2, result,
+    )
+    return result
+
+
+def reference_check(ref1, ref2, ds1, ds2, **weights):
+    """For two references, de-reference the object and perform object-based
+    semantic equivalence. The score influences the result of an edge check."""
+    type1, type2 = ref1.split("--")[0], ref2.split("--")[0]
+    result = 0.0
+
+    if type1 == type2:
+        if weights["_internal"]["versioning_checks"]:
+            result = _versioned_checks(ref1, ref2, ds1, ds2, **weights) / 100.0
+        else:
+            o1, o2 = ds1.get(ref1), ds2.get(ref2)
+            if o1 and o2:
+                result = semantically_equivalent(o1, o2, **weights) / 100.0
+
+    logger.debug(
+        "--\t\treference_check '%s' '%s'\tresult: '%s'",
+        ref1, ref2, result,
+    )
+    return result
+
+
+def list_reference_check(refs1, refs2, ds1, ds2, **weights):
+    """For objects that contain multiple references (i.e., object_refs) perform
+    the same de-reference procedure and perform object-based semantic equivalence.
+    The score influences the objects containing these references. The result is
+    weighted on the amount of unique objects that could 1) be de-referenced 2) """
+    results = {}
+    if len(refs1) >= len(refs2):
+        l1 = refs1
+        l2 = refs2
+        b1 = ds1
+        b2 = ds2
+    else:
+        l1 = refs2
+        l2 = refs1
+        b1 = ds2
+        b2 = ds1
+
+    l1.sort()
+    l2.sort()
+
+    for ref1 in l1:
+        for ref2 in l2:
+            type1, type2 = ref1.split("--")[0], ref2.split("--")[0]
+            if type1 == type2:
+                score = reference_check(ref1, ref2, b1, b2, **weights) * 100.0
+
+                if ref1 not in results:
+                    results[ref1] = {"matched": ref2, "value": score}
+                elif score > results[ref1]["value"]:
+                    results[ref1] = {"matched": ref2, "value": score}
+
+    result = 0.0
+    total_sum = sum(x["value"] for x in results.values())
+    max_score = len(results) * 100.0
+
+    if max_score > 0:
+        result = total_sum / max_score
+
+    logger.debug(
+        "--\t\tlist_reference_check '%s' '%s'\ttotal_sum: '%s'\tmax_score: '%s'\tresult: '%s'",
+        refs1, refs2, total_sum, max_score, result,
+    )
+    return result
+
+
+# default weights used for the semantic equivalence process
+WEIGHTS = {
+    "attack-pattern": {
+        "name": (30, partial_string_based),
+        "external_references": (70, partial_external_reference_based),
+    },
+    "campaign": {
+        "name": (60, partial_string_based),
+        "aliases": (40, partial_list_based),
+    },
+    "course-of-action": {
+        "name": (60, partial_string_based),
+        "external_references": (40, partial_external_reference_based),
+    },
+    "identity": {
+        "name": (60, partial_string_based),
+        "identity_class": (20, exact_match),
+        "sectors": (20, partial_list_based),
+    },
+    "indicator": {
+        "indicator_types": (15, partial_list_based),
+        "pattern": (80, custom_pattern_based),
+        "valid_from": (5, partial_timestamp_based),
+        "tdelta": 1,  # One day interval
+    },
+    "intrusion-set": {
+        "name": (20, partial_string_based),
+        "external_references": (60, partial_external_reference_based),
+        "aliases": (20, partial_list_based),
+    },
+    "location": {
+        "longitude_latitude": (34, partial_location_distance),
+        "region": (33, exact_match),
+        "country": (33, exact_match),
+        "threshold": 1000.0,
+    },
+    "malware": {
+        "malware_types": (20, partial_list_based),
+        "name": (80, partial_string_based),
+    },
+    "marking-definition": {
+        "name": (20, exact_match),
+        "definition": (60, exact_match),
+        "definition_type": (20, exact_match),
+    },
+    "threat-actor": {
+        "name": (60, partial_string_based),
+        "threat_actor_types": (20, partial_list_based),
+        "aliases": (20, partial_list_based),
+    },
+    "tool": {
+        "tool_types": (20, partial_list_based),
+        "name": (80, partial_string_based),
+    },
+    "vulnerability": {
+        "name": (30, partial_string_based),
+        "external_references": (70, partial_external_reference_based),
+    },
+    "_internal": {
+        "ignore_spec_version": False,
+    },
+}  # :autodoc-skip:
diff --git a/stix2/equivalence/patterns/__init__.py b/stix2/equivalence/pattern/__init__.py
similarity index 95%
rename from stix2/equivalence/patterns/__init__.py
rename to stix2/equivalence/pattern/__init__.py
index 85ec9ab..b2e5421 100644
--- a/stix2/equivalence/patterns/__init__.py
+++ b/stix2/equivalence/pattern/__init__.py
@@ -1,7 +1,7 @@
 """Python APIs for STIX 2 Pattern Semantic Equivalence.
 
 .. autosummary::
-   :toctree: patterns
+   :toctree: pattern
 
    compare
    transform
@@ -10,13 +10,13 @@
 """
 
 import stix2
-from stix2.equivalence.patterns.compare.observation import (
+from stix2.equivalence.pattern.compare.observation import (
     observation_expression_cmp,
 )
-from stix2.equivalence.patterns.transform import (
+from stix2.equivalence.pattern.transform import (
     ChainTransformer, SettleTransformer,
 )
-from stix2.equivalence.patterns.transform.observation import (
+from stix2.equivalence.pattern.transform.observation import (
     AbsorptionTransformer, CanonicalizeComparisonExpressionsTransformer,
     DNFTransformer, FlattenTransformer, OrderDedupeTransformer,
 )
diff --git a/stix2/equivalence/patterns/compare/__init__.py b/stix2/equivalence/pattern/compare/__init__.py
similarity index 100%
rename from stix2/equivalence/patterns/compare/__init__.py
rename to stix2/equivalence/pattern/compare/__init__.py
diff --git a/stix2/equivalence/patterns/compare/comparison.py b/stix2/equivalence/pattern/compare/comparison.py
similarity index 99%
rename from stix2/equivalence/patterns/compare/comparison.py
rename to stix2/equivalence/pattern/compare/comparison.py
index ed717fc..e412705 100644
--- a/stix2/equivalence/patterns/compare/comparison.py
+++ b/stix2/equivalence/pattern/compare/comparison.py
@@ -4,7 +4,7 @@ Comparison utilities for STIX pattern comparison expressions.
 import base64
 import functools
 
-from stix2.equivalence.patterns.compare import generic_cmp, iter_lex_cmp
+from stix2.equivalence.pattern.compare import generic_cmp, iter_lex_cmp
 from stix2.patterns import (
     AndBooleanExpression, BinaryConstant, BooleanConstant, FloatConstant,
     HexConstant, IntegerConstant, ListConstant, ListObjectPathComponent,
diff --git a/stix2/equivalence/patterns/compare/observation.py b/stix2/equivalence/pattern/compare/observation.py
similarity index 96%
rename from stix2/equivalence/patterns/compare/observation.py
rename to stix2/equivalence/pattern/compare/observation.py
index 227b8ae..8df9e3f 100644
--- a/stix2/equivalence/patterns/compare/observation.py
+++ b/stix2/equivalence/pattern/compare/observation.py
@@ -1,8 +1,8 @@
 """
 Comparison utilities for STIX pattern observation expressions.
 """
-from stix2.equivalence.patterns.compare import generic_cmp, iter_lex_cmp
-from stix2.equivalence.patterns.compare.comparison import (
+from stix2.equivalence.pattern.compare import generic_cmp, iter_lex_cmp
+from stix2.equivalence.pattern.compare.comparison import (
     comparison_expression_cmp, generic_constant_cmp,
 )
 from stix2.patterns import (
diff --git a/stix2/equivalence/patterns/transform/__init__.py b/stix2/equivalence/pattern/transform/__init__.py
similarity index 100%
rename from stix2/equivalence/patterns/transform/__init__.py
rename to stix2/equivalence/pattern/transform/__init__.py
diff --git a/stix2/equivalence/patterns/transform/comparison.py b/stix2/equivalence/pattern/transform/comparison.py
similarity index 97%
rename from stix2/equivalence/patterns/transform/comparison.py
rename to stix2/equivalence/pattern/transform/comparison.py
index 528cc9b..d0f431b 100644
--- a/stix2/equivalence/patterns/transform/comparison.py
+++ b/stix2/equivalence/pattern/transform/comparison.py
@@ -4,12 +4,12 @@ Transformation utilities for STIX pattern comparison expressions.
 import functools
 import itertools
 
-from stix2.equivalence.patterns.compare import iter_in, iter_lex_cmp
-from stix2.equivalence.patterns.compare.comparison import (
+from stix2.equivalence.pattern.compare import iter_in, iter_lex_cmp
+from stix2.equivalence.pattern.compare.comparison import (
     comparison_expression_cmp,
 )
-from stix2.equivalence.patterns.transform import Transformer
-from stix2.equivalence.patterns.transform.specials import (
+from stix2.equivalence.pattern.transform import Transformer
+from stix2.equivalence.pattern.transform.specials import (
     ipv4_addr, ipv6_addr, windows_reg_key,
 )
 from stix2.patterns import (
diff --git a/stix2/equivalence/patterns/transform/observation.py b/stix2/equivalence/pattern/transform/observation.py
similarity index 97%
rename from stix2/equivalence/patterns/transform/observation.py
rename to stix2/equivalence/pattern/transform/observation.py
index d4ee175..a8982cf 100644
--- a/stix2/equivalence/patterns/transform/observation.py
+++ b/stix2/equivalence/pattern/transform/observation.py
@@ -4,23 +4,23 @@ Transformation utilities for STIX pattern observation expressions.
 import functools
 import itertools
 
-from stix2.equivalence.patterns.compare import iter_in, iter_lex_cmp
-from stix2.equivalence.patterns.compare.observation import (
+from stix2.equivalence.pattern.compare import iter_in, iter_lex_cmp
+from stix2.equivalence.pattern.compare.observation import (
     observation_expression_cmp,
 )
-from stix2.equivalence.patterns.transform import (
+from stix2.equivalence.pattern.transform import (
     ChainTransformer, SettleTransformer, Transformer,
 )
-from stix2.equivalence.patterns.transform.comparison import (
+from stix2.equivalence.pattern.transform.comparison import (
     SpecialValueCanonicalization,
 )
-from stix2.equivalence.patterns.transform.comparison import \
+from stix2.equivalence.pattern.transform.comparison import \
     AbsorptionTransformer as CAbsorptionTransformer
-from stix2.equivalence.patterns.transform.comparison import \
+from stix2.equivalence.pattern.transform.comparison import \
     DNFTransformer as CDNFTransformer
-from stix2.equivalence.patterns.transform.comparison import \
+from stix2.equivalence.pattern.transform.comparison import \
     FlattenTransformer as CFlattenTransformer
-from stix2.equivalence.patterns.transform.comparison import \
+from stix2.equivalence.pattern.transform.comparison import \
     OrderDedupeTransformer as COrderDedupeTransformer
 from stix2.patterns import (
     AndObservationExpression, FollowedByObservationExpression,
diff --git a/stix2/equivalence/patterns/transform/specials.py b/stix2/equivalence/pattern/transform/specials.py
similarity index 99%
rename from stix2/equivalence/patterns/transform/specials.py
rename to stix2/equivalence/pattern/transform/specials.py
index b95e6bf..d3611f3 100644
--- a/stix2/equivalence/patterns/transform/specials.py
+++ b/stix2/equivalence/pattern/transform/specials.py
@@ -3,7 +3,7 @@ Some simple comparison expression canonicalization functions.
 """
 import socket
 
-from stix2.equivalence.patterns.compare.comparison import (
+from stix2.equivalence.pattern.compare.comparison import (
     object_path_to_raw_values,
 )
 
diff --git a/stix2/test/test_pattern_equivalence.py b/stix2/test/test_pattern_equivalence.py
index 6fc2adf..431322f 100644
--- a/stix2/test/test_pattern_equivalence.py
+++ b/stix2/test/test_pattern_equivalence.py
@@ -1,6 +1,6 @@
 import pytest
 
-from stix2.equivalence.patterns import (
+from stix2.equivalence.pattern import (
     equivalent_patterns, find_equivalent_patterns,
 )
 
diff --git a/stix2/test/v20/test_environment.py b/stix2/test/v20/test_environment.py
index 5afb430..34ce596 100644
--- a/stix2/test/v20/test_environment.py
+++ b/stix2/test/v20/test_environment.py
@@ -1,6 +1,10 @@
+import os
+
 import pytest
 
 import stix2
+import stix2.equivalence.graph
+import stix2.equivalence.object
 
 from .constants import (
     CAMPAIGN_ID, CAMPAIGN_KWARGS, FAKE_TIME, IDENTITY_ID, IDENTITY_KWARGS,
@@ -8,6 +12,8 @@ from .constants import (
     RELATIONSHIP_IDS,
 )
 
+FS_PATH = os.path.join(os.path.dirname(os.path.realpath(__file__)), "stix2_data")
+
 
 @pytest.fixture
 def ds():
@@ -18,7 +24,42 @@ def ds():
     rel1 = stix2.v20.Relationship(ind, 'indicates', mal, id=RELATIONSHIP_IDS[0])
     rel2 = stix2.v20.Relationship(mal, 'targets', idy, id=RELATIONSHIP_IDS[1])
     rel3 = stix2.v20.Relationship(cam, 'uses', mal, id=RELATIONSHIP_IDS[2])
-    stix_objs = [cam, idy, ind, mal, rel1, rel2, rel3]
+    reprt = stix2.v20.Report(
+        name="Malware Report",
+        published="2021-05-09T08:22:22Z",
+        labels=["campaign"],
+        object_refs=[mal.id, rel1.id, ind.id],
+    )
+    stix_objs = [cam, idy, ind, mal, rel1, rel2, rel3, reprt]
+    yield stix2.MemoryStore(stix_objs)
+
+
+@pytest.fixture
+def ds2():
+    cam = stix2.v20.Campaign(id=CAMPAIGN_ID, **CAMPAIGN_KWARGS)
+    idy = stix2.v20.Identity(id=IDENTITY_ID, **IDENTITY_KWARGS)
+    ind = stix2.v20.Indicator(id=INDICATOR_ID, created_by_ref=idy.id, **INDICATOR_KWARGS)
+    indv2 = ind.new_version(external_references=[{
+        "source_name": "unknown",
+        "url": "https://examplewebsite.com/",
+    }])
+    mal = stix2.v20.Malware(id=MALWARE_ID, created_by_ref=idy.id, **MALWARE_KWARGS)
+    malv2 = mal.new_version(external_references=[{
+        "source_name": "unknown",
+        "url": "https://examplewebsite2.com/",
+    }])
+    rel1 = stix2.v20.Relationship(ind, 'indicates', mal, id=RELATIONSHIP_IDS[0])
+    rel2 = stix2.v20.Relationship(mal, 'targets', idy, id=RELATIONSHIP_IDS[1])
+    rel3 = stix2.v20.Relationship(cam, 'uses', mal, id=RELATIONSHIP_IDS[2])
+    stix_objs = [cam, idy, ind, indv2, mal, malv2, rel1, rel2, rel3]
+    reprt = stix2.v20.Report(
+        created_by_ref=idy.id,
+        name="example",
+        labels=["campaign"],
+        published="2021-04-09T08:22:22Z",
+        object_refs=stix_objs,
+    )
+    stix_objs.append(reprt)
     yield stix2.MemoryStore(stix_objs)
 
 
@@ -370,3 +411,144 @@ def test_related_to_by_target(ds):
     assert len(resp) == 2
     assert any(x['id'] == CAMPAIGN_ID for x in resp)
     assert any(x['id'] == INDICATOR_ID for x in resp)
+
+
+def test_versioned_checks(ds, ds2):
+    weights = stix2.equivalence.graph.GRAPH_WEIGHTS.copy()
+    weights.update({
+        "_internal": {
+            "ignore_spec_version": True,
+            "versioning_checks": True,
+            "max_depth": 1,
+        },
+    })
+    score = stix2.equivalence.object._versioned_checks(INDICATOR_ID, INDICATOR_ID, ds, ds2, **weights)
+    assert round(score) == 100
+
+
+def test_semantic_check_with_versioning(ds, ds2):
+    weights = stix2.equivalence.graph.GRAPH_WEIGHTS.copy()
+    weights.update({
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": True,
+            "ds1": ds,
+            "ds2": ds2,
+            "max_depth": 1,
+        },
+    })
+    ind = stix2.v20.Indicator(
+        **dict(
+            labels=["malicious-activity"],
+            pattern="[file:hashes.'SHA-256' = 'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855']",
+            valid_from="2017-01-01T12:34:56Z",
+            external_references=[
+                {
+                  "source_name": "unknown",
+                  "url": "https://examplewebsite2.com/",
+                },
+            ],
+            object_marking_refs=[stix2.v20.TLP_WHITE],
+        )
+    )
+    ds.add(ind)
+    score = stix2.equivalence.object.reference_check(ind.id, INDICATOR_ID, ds, ds2, **weights)
+    assert round(score) == 0  # Since pattern is different score is really low
+
+
+def test_list_semantic_check(ds, ds2):
+    weights = stix2.equivalence.graph.GRAPH_WEIGHTS.copy()
+    weights.update({
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": False,
+            "ds1": ds,
+            "ds2": ds2,
+            "max_depth": 1,
+        },
+    })
+    object_refs1 = [
+        "malware--9c4638ec-f1de-4ddb-abf4-1b760417654e",
+        "relationship--06520621-5352-4e6a-b976-e8fa3d437ffd",
+        "indicator--a740531e-63ff-4e49-a9e1-a0a3eed0e3e7",
+    ]
+    object_refs2 = [
+        "campaign--8e2e2d2b-17d4-4cbf-938f-98ee46b3cd3f",
+        "identity--311b2d2d-f010-4473-83ec-1edf84858f4c",
+        "indicator--a740531e-63ff-4e49-a9e1-a0a3eed0e3e7",
+        "malware--9c4638ec-f1de-4ddb-abf4-1b760417654e",
+        "malware--9c4638ec-f1de-4ddb-abf4-1b760417654e",
+        "relationship--06520621-5352-4e6a-b976-e8fa3d437ffd",
+        "relationship--181c9c09-43e6-45dd-9374-3bec192f05ef",
+        "relationship--a0cbb21c-8daf-4a7f-96aa-7155a4ef8f70",
+    ]
+
+    score = stix2.equivalence.object.list_reference_check(
+        object_refs1,
+        object_refs2,
+        ds,
+        ds2,
+        **weights,
+    )
+    assert round(score) == 1
+
+
+def test_graph_equivalence_with_filesystem_source(ds):
+    weights = {
+        "_internal": {
+            "ignore_spec_version": True,
+            "versioning_checks": False,
+            "max_depth": 1,
+        },
+    }
+    prop_scores = {}
+    fs = stix2.FileSystemSource(FS_PATH)
+    env = stix2.Environment().graphically_equivalent(fs, ds, prop_scores, **weights)
+    assert round(env) == 28
+    assert round(prop_scores["matching_score"]) == 139
+    assert round(prop_scores["sum_weights"]) == 500
+
+
+def test_graph_equivalence_with_duplicate_graph(ds):
+    weights = {
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": False,
+            "max_depth": 1,
+        },
+    }
+    prop_scores = {}
+    env = stix2.Environment().graphically_equivalent(ds, ds, prop_scores, **weights)
+    assert round(env) == 100
+    assert round(prop_scores["matching_score"]) == 800
+    assert round(prop_scores["sum_weights"]) == 800
+
+
+def test_graph_equivalence_with_versioning_check_on(ds2, ds):
+    weights = {
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": True,
+            "max_depth": 1,
+        },
+    }
+    prop_scores = {}
+    env = stix2.Environment().graphically_equivalent(ds, ds2, prop_scores, **weights)
+    assert round(env) == 93
+    assert round(prop_scores["matching_score"]) == 745
+    assert round(prop_scores["sum_weights"]) == 800
+
+
+def test_graph_equivalence_with_versioning_check_off(ds2, ds):
+    weights = {
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": False,
+            "max_depth": 1,
+        },
+    }
+    prop_scores = {}
+    env = stix2.Environment().graphically_equivalent(ds, ds2, prop_scores, **weights)
+    assert round(env) == 93
+    assert round(prop_scores["matching_score"]) == 745
+    assert round(prop_scores["sum_weights"]) == 800
diff --git a/stix2/test/v20/test_pattern_equivalence.py b/stix2/test/v20/test_pattern_equivalence.py
index 1ada5c7..aab8533 100644
--- a/stix2/test/v20/test_pattern_equivalence.py
+++ b/stix2/test/v20/test_pattern_equivalence.py
@@ -4,7 +4,7 @@ Pattern equivalence unit tests which use STIX 2.0-specific pattern features
 
 import pytest
 
-from stix2.equivalence.patterns import equivalent_patterns
+from stix2.equivalence.pattern import equivalent_patterns
 
 
 @pytest.mark.parametrize(
diff --git a/stix2/test/v20/test_utils.py b/stix2/test/v20/test_utils.py
index 9372bbb..a66f3e8 100644
--- a/stix2/test/v20/test_utils.py
+++ b/stix2/test/v20/test_utils.py
@@ -114,7 +114,7 @@ def test_deduplicate(stix_objs1):
     mods = [obj['modified'] for obj in unique]
 
     assert "indicator--00000000-0000-4000-8000-000000000001" in ids
-    assert "indicator--00000000-0000-4000-8000-000000000001" in ids
+    assert "indicator--00000000-0000-4000-8000-000000000002" in ids
     assert "2017-01-27T13:49:53.935Z" in mods
     assert "2017-01-27T13:49:53.936Z" in mods
 
diff --git a/stix2/test/v21/conftest.py b/stix2/test/v21/conftest.py
index d602f42..6efcf39 100644
--- a/stix2/test/v21/conftest.py
+++ b/stix2/test/v21/conftest.py
@@ -132,7 +132,13 @@ def stix_objs1():
         "type": "indicator",
         "valid_from": "2017-01-27T13:49:53.935382Z",
     }
-    return [ind1, ind2, ind3, ind4, ind5]
+    sco = {
+        "type": "url",
+        "spec_version": "2.1",
+        "id": "url--cc1deced-d99b-4d72-9268-8182420cb2fd",
+        "value": "http://example.com/",
+    }
+    return [ind1, ind2, ind3, ind4, ind5, sco]
 
 
 @pytest.fixture
diff --git a/stix2/test/v21/test_datastore_composite.py b/stix2/test/v21/test_datastore_composite.py
index 76119c3..c6128e5 100644
--- a/stix2/test/v21/test_datastore_composite.py
+++ b/stix2/test/v21/test_datastore_composite.py
@@ -59,6 +59,17 @@ def test_composite_datasource_operations(stix_objs1, stix_objs2):
     assert indicator["modified"] == parse_into_datetime("2017-01-31T13:49:53.935Z")
     assert indicator["type"] == "indicator"
 
+    sco = cds1.get("url--cc1deced-d99b-4d72-9268-8182420cb2fd")
+    assert sco["id"] == "url--cc1deced-d99b-4d72-9268-8182420cb2fd"
+
+    scos = cds1.all_versions("url--cc1deced-d99b-4d72-9268-8182420cb2fd")
+    assert len(scos) == 1
+    assert scos[0]["id"] == "url--cc1deced-d99b-4d72-9268-8182420cb2fd"
+
+    scos = cds1.query([Filter("value", "=", "http://example.com/")])
+    assert len(scos) == 1
+    assert scos[0]["id"] == "url--cc1deced-d99b-4d72-9268-8182420cb2fd"
+
     query1 = [
         Filter("type", "=", "indicator"),
     ]
diff --git a/stix2/test/v21/test_environment.py b/stix2/test/v21/test_environment.py
index 7a7d4c1..95094fe 100644
--- a/stix2/test/v21/test_environment.py
+++ b/stix2/test/v21/test_environment.py
@@ -1,7 +1,11 @@
+import os
+
 import pytest
 
 import stix2
 import stix2.environment
+import stix2.equivalence.graph
+import stix2.equivalence.object
 import stix2.exceptions
 
 from .constants import (
@@ -12,6 +16,8 @@ from .constants import (
     VULNERABILITY_ID, VULNERABILITY_KWARGS,
 )
 
+FS_PATH = os.path.join(os.path.dirname(os.path.realpath(__file__)), "stix2_data")
+
 
 @pytest.fixture
 def ds():
@@ -22,7 +28,46 @@ def ds():
     rel1 = stix2.v21.Relationship(ind, 'indicates', mal, id=RELATIONSHIP_IDS[0])
     rel2 = stix2.v21.Relationship(mal, 'targets', idy, id=RELATIONSHIP_IDS[1])
     rel3 = stix2.v21.Relationship(cam, 'uses', mal, id=RELATIONSHIP_IDS[2])
-    stix_objs = [cam, idy, ind, mal, rel1, rel2, rel3]
+    reprt = stix2.v21.Report(
+        name="Malware Report", published="2021-05-09T08:22:22Z",
+        object_refs=[mal.id, rel1.id, ind.id],
+    )
+    stix_objs = [cam, idy, ind, mal, rel1, rel2, rel3, reprt]
+    yield stix2.MemoryStore(stix_objs)
+
+
+@pytest.fixture
+def ds2():
+    cam = stix2.v21.Campaign(id=CAMPAIGN_ID, **CAMPAIGN_KWARGS)
+    idy = stix2.v21.Identity(id=IDENTITY_ID, **IDENTITY_KWARGS)
+    ind = stix2.v21.Indicator(id=INDICATOR_ID, created_by_ref=idy.id, **INDICATOR_KWARGS)
+    indv2 = ind.new_version(
+        external_references=[
+            {
+                "source_name": "unknown",
+                "url": "https://examplewebsite.com/",
+            },
+        ],
+        object_marking_refs=[stix2.v21.TLP_WHITE],
+    )
+    mal = stix2.v21.Malware(id=MALWARE_ID, created_by_ref=idy.id, **MALWARE_KWARGS)
+    malv2 = mal.new_version(
+        external_references=[
+            {
+                "source_name": "unknown",
+                "url": "https://examplewebsite2.com/",
+            },
+        ],
+    )
+    rel1 = stix2.v21.Relationship(ind, 'indicates', mal, id=RELATIONSHIP_IDS[0])
+    rel2 = stix2.v21.Relationship(mal, 'targets', idy, id=RELATIONSHIP_IDS[1])
+    rel3 = stix2.v21.Relationship(cam, 'uses', mal, id=RELATIONSHIP_IDS[2])
+    stix_objs = [cam, idy, ind, indv2, mal, malv2, rel1, rel2, rel3]
+    reprt = stix2.v21.Report(
+        created_by_ref=idy.id, name="example",
+        published="2021-04-09T08:22:22Z", object_refs=stix_objs,
+    )
+    stix_objs.append(reprt)
     yield stix2.MemoryStore(stix_objs)
 
 
@@ -820,3 +865,145 @@ def test_semantic_equivalence_prop_scores_method_provided():
     assert len(prop_scores) == 2
     assert prop_scores["matching_score"] == 96.0
     assert prop_scores["sum_weights"] == 100.0
+
+
+def test_versioned_checks(ds, ds2):
+    weights = stix2.equivalence.graph.GRAPH_WEIGHTS.copy()
+    weights.update({
+        "_internal": {
+            "ignore_spec_version": True,
+            "versioning_checks": True,
+            "max_depth": 1,
+        },
+    })
+    score = stix2.equivalence.object._versioned_checks(INDICATOR_ID, INDICATOR_ID, ds, ds2, **weights)
+    assert round(score) == 100
+
+
+def test_semantic_check_with_versioning(ds, ds2):
+    weights = stix2.equivalence.graph.GRAPH_WEIGHTS.copy()
+    weights.update({
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": True,
+            "ds1": ds,
+            "ds2": ds2,
+            "max_depth": 1,
+        },
+    })
+    ind = stix2.v21.Indicator(
+        **dict(
+            indicator_types=["malicious-activity"],
+            pattern_type="stix",
+            pattern="[file:hashes.'SHA-256' = 'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855']",
+            valid_from="2017-01-01T12:34:56Z",
+            external_references=[
+                {
+                  "source_name": "unknown",
+                  "url": "https://examplewebsite2.com/",
+                },
+            ],
+            object_marking_refs=[stix2.v21.TLP_WHITE],
+        )
+    )
+    ds.add(ind)
+    score = stix2.equivalence.object.reference_check(ind.id, INDICATOR_ID, ds, ds2, **weights)
+    assert round(score) == 0  # Since pattern is different score is really low
+
+
+def test_list_semantic_check(ds, ds2):
+    weights = stix2.equivalence.graph.GRAPH_WEIGHTS.copy()
+    weights.update({
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": False,
+            "ds1": ds,
+            "ds2": ds2,
+            "max_depth": 1,
+        },
+    })
+    object_refs1 = [
+        "malware--9c4638ec-f1de-4ddb-abf4-1b760417654e",
+        "relationship--06520621-5352-4e6a-b976-e8fa3d437ffd",
+        "indicator--a740531e-63ff-4e49-a9e1-a0a3eed0e3e7",
+    ]
+    object_refs2 = [
+        "campaign--8e2e2d2b-17d4-4cbf-938f-98ee46b3cd3f",
+        "identity--311b2d2d-f010-4473-83ec-1edf84858f4c",
+        "indicator--a740531e-63ff-4e49-a9e1-a0a3eed0e3e7",
+        "malware--9c4638ec-f1de-4ddb-abf4-1b760417654e",
+        "malware--9c4638ec-f1de-4ddb-abf4-1b760417654e",
+        "relationship--06520621-5352-4e6a-b976-e8fa3d437ffd",
+        "relationship--181c9c09-43e6-45dd-9374-3bec192f05ef",
+        "relationship--a0cbb21c-8daf-4a7f-96aa-7155a4ef8f70",
+    ]
+
+    score = stix2.equivalence.object.list_reference_check(
+        object_refs1,
+        object_refs2,
+        ds,
+        ds2,
+        **weights,
+    )
+    assert round(score) == 1
+
+
+def test_graph_equivalence_with_filesystem_source(ds):
+    weights = {
+        "_internal": {
+            "ignore_spec_version": True,
+            "versioning_checks": False,
+            "max_depth": 1,
+        },
+    }
+    prop_scores = {}
+    fs = stix2.FileSystemSource(FS_PATH)
+    env = stix2.Environment().graphically_equivalent(fs, ds, prop_scores, **weights)
+    assert round(env) == 24
+    assert round(prop_scores["matching_score"]) == 122
+    assert round(prop_scores["sum_weights"]) == 500
+
+
+def test_graph_equivalence_with_duplicate_graph(ds):
+    weights = {
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": False,
+            "max_depth": 1,
+        },
+    }
+    prop_scores = {}
+    env = stix2.Environment().graphically_equivalent(ds, ds, prop_scores, **weights)
+    assert round(env) == 100
+    assert round(prop_scores["matching_score"]) == 800
+    assert round(prop_scores["sum_weights"]) == 800
+
+
+def test_graph_equivalence_with_versioning_check_on(ds2, ds):
+    weights = {
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": True,
+            "max_depth": 1,
+        },
+    }
+    prop_scores = {}
+    env = stix2.Environment().graphically_equivalent(ds, ds2, prop_scores, **weights)
+    assert round(env) == 93
+    assert round(prop_scores["matching_score"]) == 745
+    assert round(prop_scores["sum_weights"]) == 800
+
+
+def test_graph_equivalence_with_versioning_check_off(ds2, ds):
+    weights = {
+        "_internal": {
+            "ignore_spec_version": False,
+            "versioning_checks": False,
+            "max_depth": 1,
+        },
+    }
+    prop_scores = {}
+    env = stix2.Environment().graphically_equivalent(ds, ds2, prop_scores, **weights)
+    assert round(env) == 93
+    assert round(prop_scores["matching_score"]) == 745
+    assert round(prop_scores["sum_weights"]) == 800
diff --git a/stix2/test/v21/test_pattern_equivalence.py b/stix2/test/v21/test_pattern_equivalence.py
index 71ded69..5f6b707 100644
--- a/stix2/test/v21/test_pattern_equivalence.py
+++ b/stix2/test/v21/test_pattern_equivalence.py
@@ -4,7 +4,7 @@ Pattern equivalence unit tests which use STIX 2.1+-specific pattern features
 
 import pytest
 
-from stix2.equivalence.patterns import equivalent_patterns
+from stix2.equivalence.pattern import equivalent_patterns
 
 
 @pytest.mark.parametrize(
diff --git a/stix2/test/v21/test_utils.py b/stix2/test/v21/test_utils.py
index 03477aa..f64cec2 100644
--- a/stix2/test/v21/test_utils.py
+++ b/stix2/test/v21/test_utils.py
@@ -104,17 +104,18 @@ def test_get_type_from_id(stix_id, type):
 def test_deduplicate(stix_objs1):
     unique = stix2.utils.deduplicate(stix_objs1)
 
-    # Only 3 objects are unique
-    # 2 id's vary
+    # Only 4 objects are unique
+    # 3 id's vary
     # 2 modified times vary for a particular id
 
-    assert len(unique) == 3
+    assert len(unique) == 4
 
     ids = [obj['id'] for obj in unique]
-    mods = [obj['modified'] for obj in unique]
+    mods = [obj.get('modified') for obj in unique]
 
     assert "indicator--00000000-0000-4000-8000-000000000001" in ids
-    assert "indicator--00000000-0000-4000-8000-000000000001" in ids
+    assert "indicator--00000000-0000-4000-8000-000000000002" in ids
+    assert "url--cc1deced-d99b-4d72-9268-8182420cb2fd" in ids
     assert "2017-01-27T13:49:53.935Z" in mods
     assert "2017-01-27T13:49:53.936Z" in mods
 
diff --git a/stix2/utils.py b/stix2/utils.py
index f741581..1b88f72 100644
--- a/stix2/utils.py
+++ b/stix2/utils.py
@@ -132,11 +132,12 @@ def deduplicate(stix_obj_list):
     unique_objs = {}
 
     for obj in stix_obj_list:
-        try:
-            unique_objs[(obj['id'], obj['modified'])] = obj
-        except KeyError:
-            # Handle objects with no `modified` property, e.g. marking-definition
-            unique_objs[(obj['id'], obj['created'])] = obj
+        ver = obj.get("modified") or obj.get("created")
+
+        if ver is None:
+            unique_objs[obj["id"]] = obj
+        else:
+            unique_objs[(obj['id'], ver)] = obj
 
     return list(unique_objs.values())