diff --git a/stix2/patterns.py b/stix2/patterns.py
index 9656ff1..2e149be 100644
--- a/stix2/patterns.py
+++ b/stix2/patterns.py
@@ -135,6 +135,7 @@ _HASH_REGEX = {
     "SHA3512": ("^[a-fA-F0-9]{128}$", "SHA3-512"),
     "SSDEEP": ("^[a-zA-Z0-9/+:.]{1,128}$", "ssdeep"),
     "WHIRLPOOL": ("^[a-fA-F0-9]{128}$", "WHIRLPOOL"),
+    "TLSH": ("^[a-fA-F0-9]{70}$", "TLSH"),
 }
 
 
diff --git a/stix2/properties.py b/stix2/properties.py
index c956a08..f6211c8 100644
--- a/stix2/properties.py
+++ b/stix2/properties.py
@@ -363,6 +363,10 @@ class DictionaryProperty(Property):
                     "underscore (_)"
                 )
                 raise DictionaryKeyError(k, msg)
+
+        if len(dictified) < 1:
+            raise ValueError("must not be empty.")
+
         return dictified
 
 
@@ -381,6 +385,7 @@ HASHES_REGEX = {
     "SHA3512": (r"^[a-fA-F0-9]{128}$", "SHA3-512"),
     "SSDEEP": (r"^[a-zA-Z0-9/+:.]{1,128}$", "ssdeep"),
     "WHIRLPOOL": (r"^[a-fA-F0-9]{128}$", "WHIRLPOOL"),
+    "TLSH": (r"^[a-fA-F0-9]{70}$", "TLSH"),
 }
 
 
diff --git a/stix2/test/v21/test_bundle.py b/stix2/test/v21/test_bundle.py
index 54ef318..4e30c84 100644
--- a/stix2/test/v21/test_bundle.py
+++ b/stix2/test/v21/test_bundle.py
@@ -22,6 +22,7 @@ EXPECTED_BUNDLE = """{
             ],
             "pattern": "[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']",
             "pattern_type": "stix",
+            "pattern_version": "2.1",
             "valid_from": "2017-01-01T12:34:56Z"
         },
         {
@@ -61,6 +62,7 @@ EXPECTED_BUNDLE_DICT = {
             "modified": "2017-01-01T12:34:56.000Z",
             "pattern": "[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']",
             "pattern_type": "stix",
+            "pattern_version": "2.1",
             "valid_from": "2017-01-01T12:34:56Z",
             "indicator_types": [
                 "malicious-activity",
diff --git a/stix2/test/v21/test_indicator.py b/stix2/test/v21/test_indicator.py
index ea46d6d..0562dfd 100644
--- a/stix2/test/v21/test_indicator.py
+++ b/stix2/test/v21/test_indicator.py
@@ -19,6 +19,7 @@ EXPECTED_INDICATOR = """{
     ],
     "pattern": "[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']",
     "pattern_type": "stix",
+    "pattern_version": "2.1",
     "valid_from": "1970-01-01T00:00:01Z"
 }"""
 
@@ -31,6 +32,7 @@ EXPECTED_INDICATOR_REPR = "Indicator(" + " ".join("""
     indicator_types=['malicious-activity'],
     pattern="[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']",
     pattern_type='stix',
+    pattern_version='2.1',
     valid_from='1970-01-01T00:00:01Z'
 """.split()) + ")"
 
diff --git a/stix2/test/v21/test_observed_data.py b/stix2/test/v21/test_observed_data.py
index 0074bf7..2910ba1 100644
--- a/stix2/test/v21/test_observed_data.py
+++ b/stix2/test/v21/test_observed_data.py
@@ -1117,6 +1117,28 @@ def test_network_traffic_socket_example():
     assert nt.extensions['socket-ext'].socket_type == "SOCK_STREAM"
 
 
+def test_incorrect_socket_options():
+    with pytest.raises(ValueError) as excinfo:
+        stix2.v21.SocketExt(
+            is_listening=True,
+            address_family="AF_INET",
+            protocol_family="PF_INET",
+            socket_type="SOCK_STREAM",
+            options={"RCVTIMEO": 100},
+        )
+    assert "Incorrect options key" == str(excinfo.value)
+
+    with pytest.raises(ValueError) as excinfo:
+        stix2.v21.SocketExt(
+            is_listening=True,
+            address_family="AF_INET",
+            protocol_family="PF_INET",
+            socket_type="SOCK_STREAM",
+            options={"SO_RCVTIMEO": '100'},
+        )
+    assert "Options value must be an integer" == str(excinfo.value)
+
+
 def test_network_traffic_tcp_example():
     h = stix2.v21.TCPExt(src_flags_hex="00000002")
     nt = stix2.v21.NetworkTraffic(
@@ -1366,6 +1388,18 @@ def test_x509_certificate_example():
     assert x509.subject == "C=US, ST=Maryland, L=Pasadena, O=Brent Baccala, OU=FreeSoft, CN=www.freesoft.org/emailAddress=baccala@freesoft.org"  # noqa
 
 
+def test_x509_certificate_error():
+
+    with pytest.raises(stix2.exceptions.PropertyPresenceError) as excinfo:
+        stix2.v21.X509Certificate(
+            defanged=True,
+        )
+
+    assert excinfo.value.cls == stix2.v21.X509Certificate
+    assert "At least one of the" in str(excinfo.value)
+    assert "properties for X509Certificate must be populated." in str(excinfo.value)
+
+
 def test_new_version_with_related_objects():
     data = stix2.v21.ObservedData(
         first_observed="2016-03-12T12:00:00Z",
diff --git a/stix2/test/v21/test_properties.py b/stix2/test/v21/test_properties.py
index 1fb3cc4..50bce17 100644
--- a/stix2/test/v21/test_properties.py
+++ b/stix2/test/v21/test_properties.py
@@ -72,6 +72,14 @@ def test_list_property():
         p.clean([])
 
 
+def test_dictionary_property():
+    p = DictionaryProperty(StringProperty)
+
+    assert p.clean({'spec_version': '2.1'})
+    with pytest.raises(ValueError):
+        p.clean({})
+
+
 def test_string_property():
     prop = StringProperty()
 
@@ -411,6 +419,7 @@ def test_property_list_of_dictionary():
     "value", [
         {"sha256": "6db12788c37247f2316052e142f42f4b259d6561751e5f401a1ae2a6df9c674b"},
         [('MD5', '2dfb1bcc980200c6706feee399d41b3f'), ('RIPEMD-160', 'b3a8cd8a27c90af79b3c81754f267780f443dfef')],
+        [('TLSH', '6FF02BEF718027B0160B4391212923ED7F1A463D563B1549B86CF62973B197AD2731F8')],
     ],
 )
 def test_hashes_property_valid(value):
@@ -422,6 +431,7 @@ def test_hashes_property_valid(value):
     "value", [
         {"MD5": "a"},
         {"SHA-256": "2dfb1bcc980200c6706feee399d41b3f"},
+        {"TLSH": "6FF02BEF718027B0160B4391212923ED7F1A463D563B1549B86CF62973B197AD2731F"},
     ],
 )
 def test_hashes_property_invalid(value):
diff --git a/stix2/v21/observables.py b/stix2/v21/observables.py
index 0d27bb4..fdb61f4 100644
--- a/stix2/v21/observables.py
+++ b/stix2/v21/observables.py
@@ -592,6 +592,18 @@ class SocketExt(_Extension):
         ('socket_handle', IntegerProperty()),
     ])
 
+    def _check_object_constraints(self):
+        super(SocketExt, self)._check_object_constraints()
+
+        options = self.get('options')
+
+        if options is not None:
+            for key, val in options.items():
+                if key[:3] != "SO_":
+                    raise ValueError("Incorrect options key")
+                if not isinstance(val, int):
+                    raise ValueError("Options value must be an integer")
+
 
 class TCPExt(_Extension):
     # TODO: Add link
@@ -986,6 +998,18 @@ class X509Certificate(_Observable):
     ])
     _id_contributing_properties = ["hashes", "serial_number"]
 
+    def _check_object_constraints(self):
+        super(X509Certificate, self)._check_object_constraints()
+
+        att_list = [
+                'is_self_signed', 'hashes', 'version', 'serial_number',
+                'signature_algorithm', 'issuer', 'validity_not_before',
+                'validity_not_after', 'subject', 'subject_public_key_algorithm',
+                'subject_public_key_modulus', 'subject_public_key_exponent',
+                'x509_v3_extensions',
+        ]
+        self._check_at_least_one_property(att_list)
+
 
 def CustomObservable(type='x-custom-observable', properties=None):
     """Custom STIX Cyber Observable Object type decorator.
diff --git a/stix2/v21/sdo.py b/stix2/v21/sdo.py
index 7cd7891..6f7b52d 100644
--- a/stix2/v21/sdo.py
+++ b/stix2/v21/sdo.py
@@ -215,6 +215,13 @@ class Indicator(STIXDomainObject):
         ('granular_markings', ListProperty(GranularMarking)),
     ])
 
+    def __init__(self, *args, **kwargs):
+
+        if kwargs.get('pattern') and kwargs.get('pattern_type') == 'stix' and not kwargs.get('pattern_version'):
+            kwargs['pattern_version'] = '2.1'
+
+        super(STIXDomainObject, self).__init__(*args, **kwargs)
+
     def _check_object_constraints(self):
         super(Indicator, self)._check_object_constraints()