diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec6d178454..11cc3c89a6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,70 @@
+Changes in [1.5.9](https://github.com/vector-im/riot-web/releases/tag/v1.5.9) (2020-02-17)
+==========================================================================================
+[Full Changelog](https://github.com/vector-im/riot-web/compare/v1.5.9-rc.1...v1.5.9)
+
+ * Automate SDK dep upgrades for release
+   [\#12374](https://github.com/vector-im/riot-web/pull/12374)
+
+Changes in [1.5.9-rc.1](https://github.com/vector-im/riot-web/releases/tag/v1.5.9-rc.1) (2020-02-13)
+====================================================================================================
+[Full Changelog](https://github.com/vector-im/riot-web/compare/v1.5.8...v1.5.9-rc.1)
+
+ * Upgrade JS SDK to 5.0.0-rc.1 and React SDK 2.1.0-rc.2
+ * Update from Weblate
+   [\#12354](https://github.com/vector-im/riot-web/pull/12354)
+ * Add top left menu shortcut
+   [\#12310](https://github.com/vector-im/riot-web/pull/12310)
+ * Remove modernizr rules for features on which we only soft depend
+   [\#12272](https://github.com/vector-im/riot-web/pull/12272)
+ * Embed CSP meta tag and stop using script-src unsafe-inline
+   [\#12258](https://github.com/vector-im/riot-web/pull/12258)
+ * Add contribute.json
+   [\#12251](https://github.com/vector-im/riot-web/pull/12251)
+ * Improve Browser checks
+   [\#12232](https://github.com/vector-im/riot-web/pull/12232)
+ * Document padlock flag
+   [\#12173](https://github.com/vector-im/riot-web/pull/12173)
+ * Enable cross-signing on /develop
+   [\#12126](https://github.com/vector-im/riot-web/pull/12126)
+ * Switch back to legacy decorators
+   [\#12110](https://github.com/vector-im/riot-web/pull/12110)
+ * Update babel targets
+   [\#12102](https://github.com/vector-im/riot-web/pull/12102)
+ * Install deps for linting
+   [\#12076](https://github.com/vector-im/riot-web/pull/12076)
+ * Update from Weblate
+   [\#12062](https://github.com/vector-im/riot-web/pull/12062)
+ * Change to minimal Webpack output
+   [\#12049](https://github.com/vector-im/riot-web/pull/12049)
+ * Remove docs for new invite dialog labs feature
+   [\#12015](https://github.com/vector-im/riot-web/pull/12015)
+ * ElectronPlatform: Add the indexSize method.
+   [\#11529](https://github.com/vector-im/riot-web/pull/11529)
+ * ElectronPlatform: Add the ability to load file events from the event index
+   [\#11907](https://github.com/vector-im/riot-web/pull/11907)
+ * Fix the remainder of the cookie links
+   [\#12008](https://github.com/vector-im/riot-web/pull/12008)
+ * Use bash in Docker scripts
+   [\#12001](https://github.com/vector-im/riot-web/pull/12001)
+ * Use debian to build the Docker image
+   [\#11999](https://github.com/vector-im/riot-web/pull/11999)
+ * Update cookie policy urls on /app and /develop config.json
+   [\#11998](https://github.com/vector-im/riot-web/pull/11998)
+ * BuildKite: Only deploy to /develop if everything else passed
+   [\#11996](https://github.com/vector-im/riot-web/pull/11996)
+ * Add docs for admin report content message
+   [\#11995](https://github.com/vector-im/riot-web/pull/11995)
+ * Load as little as possible in index.js for the skinner
+   [\#11959](https://github.com/vector-im/riot-web/pull/11959)
+ * Fix webpack config (by stealing Dave's config)
+   [\#11956](https://github.com/vector-im/riot-web/pull/11956)
+ * Force Jest to resolve the js-sdk and react-sdk to src directories
+   [\#11954](https://github.com/vector-im/riot-web/pull/11954)
+ * Fix build to not babel modules inside js/react sdk
+   [\#11949](https://github.com/vector-im/riot-web/pull/11949)
+ * Fix webpack to babel js-sdk & react-sdk but no other deps
+   [\#11944](https://github.com/vector-im/riot-web/pull/11944)
+
 Changes in [1.5.8](https://github.com/vector-im/riot-web/releases/tag/v1.5.8) (2020-01-27)
 ==========================================================================================
 [Full Changelog](https://github.com/vector-im/riot-web/compare/v1.5.8-rc.2...v1.5.8)
diff --git a/README.md b/README.md
index c4f63d960a..edbb1ada57 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,29 @@
 Riot
 ====
 
-Riot (formerly known as Vector) is a Matrix web client built using the [Matrix React SDK](https://github.com/matrix-org/matrix-react-sdk).
+Riot (formerly known as Vector) is a Matrix web client built using the [Matrix
+React SDK](https://github.com/matrix-org/matrix-react-sdk).
 
-Riot is officially supported on the web in the last 2 major versions of Chrome, Firefox, and Safari. For Riot on Desktop (electron),
-only the officially published app is supported. Other browsers and packages may work, however official support is not provided.
-For accessing Riot on an Android or iOS device, check out [riot-android](https://github.com/vector-im/riot-android)
-and [riot-ios](https://github.com/vector-im/riot-ios) - riot-web does not support mobile devices.
+Supported Environments
+======================
+
+Riot has several tiers of support for different environments:
+
+* Supported
+  * Definition: Issues **actively triaged**, regressions **block** the release
+  * Last 2 major versions of Chrome, Firefox, and Safari
+  * Latest release of official Riot Desktop app on macOS, Windows, and Linux versions that are actively supported by the OS vendor and receive security updates
+* Experimental
+  * Definition: Issues **accepted**, regressions **do not block** the release
+  * Riot as an installed PWA via current stable version of Chrome, Firefox, and Safari
+  * Mobile web for current stable version of Chrome, Firefox, and Safari on Android, iOS, and iPadOS
+* Not supported
+  * Definition: Issues only affecting unsupported environments are **closed**
+  * Everything else
+
+For accessing Riot on an Android or iOS device, we currently recommend the
+native apps [riot-android](https://github.com/vector-im/riot-android)
+and [riot-ios](https://github.com/vector-im/riot-ios).
 
 Getting Started
 ===============
diff --git a/electron_app/package.json b/electron_app/package.json
index 4af708ae33..11e2cf5c7e 100644
--- a/electron_app/package.json
+++ b/electron_app/package.json
@@ -2,7 +2,7 @@
   "name": "riot-web",
   "productName": "Riot",
   "main": "src/electron-main.js",
-  "version": "1.5.8",
+  "version": "1.5.9",
   "description": "A feature-rich client for Matrix.org",
   "author": "New Vector Ltd.",
   "dependencies": {
diff --git a/package.json b/package.json
index 62b7121ea0..59bb4947d7 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "name": "riot-web",
   "productName": "Riot",
   "main": "electron_app/src/electron-main.js",
-  "version": "1.5.8",
+  "version": "1.5.9",
   "description": "A feature-rich client for Matrix.org",
   "author": "New Vector Ltd.",
   "repository": {
@@ -191,7 +191,9 @@
     "afterSign": "scripts/electron_afterSign.js"
   },
   "jest": {
-    "modulePathIgnorePatterns": ["<rootDir>/electron_app"],
+    "modulePathIgnorePatterns": [
+      "<rootDir>/electron_app"
+    ],
     "testEnvironment": "jest-environment-jsdom-fourteen",
     "testMatch": [
       "<rootDir>/test/**/*-test.js"
diff --git a/release.sh b/release.sh
index 33b3676f1b..753e182069 100755
--- a/release.sh
+++ b/release.sh
@@ -21,25 +21,40 @@ cd `dirname $0`
 for i in matrix-js-sdk matrix-react-sdk
 do
     depver=`cat package.json | jq -r .dependencies[\"$i\"]`
-    latestver=`yarn info -s $i version`
+    latestver=`yarn info -s $i dist-tags.next`
     if [ "$depver" != "$latestver" ]
     then
-        echo "The latest version of $i is $latestver but package.json depends on $depver"
-        echo -n "Type 'Yes' to continue anyway: "
+        echo "The latest version of $i is $latestver but package.json depends on $depver."
+        echo -n "Type 'u' to auto-upgrade, 'c' to continue anyway, or 'a' to abort:"
         read resp
-        if [ "$resp" != "Yes" ]
+        if [ "$resp" != "u" ] && [ "$resp" != "c" ]
         then
-            echo "OK, never mind."
+            echo "Aborting."
             exit 1
         fi
+        if [ "$resp" == "u" ]
+        then
+            echo "Upgrading $i to $latestver..."
+            yarn add -E $i@$latestver
+            git add -u
+            # The `-e` flag opens the editor and gives you a chance to check
+            # the upgrade for correctness.
+            git commit -m "Upgrade $i to $latestver" -e
+        fi
     fi
 done
 
-# bump Electron's package.json first
 release="${1#v}"
 tag="v${release}"
-echo "electron yarn version"
+prerelease=0
+# We check if this build is a prerelease by looking to
+# see if the version has a hyphen in it. Crude,
+# but semver doesn't support postreleases so anything
+# with a hyphen is a prerelease.
+echo $release | grep -q '-' && prerelease=1
 
+# bump Electron's package.json first
+echo "electron yarn version"
 cd electron_app
 yarn version --no-git-tag-version --new-version "$release"
 git commit package.json -m "$tag"
@@ -47,3 +62,16 @@ git commit package.json -m "$tag"
 cd ..
 
 exec ./node_modules/matrix-js-sdk/release.sh -u vector-im -z "$orig_args"
+
+if [ $prerelease -eq 0 ]
+then
+    # For a release, reset SDK deps back to the `develop` branch.
+    for i in matrix-js-sdk matrix-react-sdk
+    do
+        echo "Resetting $i to develop branch..."
+        yarn add github:matrix-org/$i#develop
+        git add -u
+        git commit -m "Reset $i back to develop branch"
+    done
+    git push origin develop
+fi
diff --git a/yarn.lock b/yarn.lock
index 9b7b59dfbf..56da094581 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7595,9 +7595,10 @@ mathml-tag-names@^2.1.1:
   resolved "https://registry.yarnpkg.com/mathml-tag-names/-/mathml-tag-names-2.1.1.tgz#6dff66c99d55ecf739ca53c492e626f1d12a33cc"
   integrity sha512-pWB896KPGSGkp1XtyzRBftpTzwSOL0Gfk0wLvxt4f2mgzjY19o0LxJ3U25vNWTzsh7da+KTbuXQoQ3lOJZ8WHw==
 
-"matrix-js-sdk@github:matrix-org/matrix-js-sdk#develop":
-  version "4.0.0"
-  resolved "https://codeload.github.com/matrix-org/matrix-js-sdk/tar.gz/21e4c597d9633aef606871cf9ffffaf039142be3"
+matrix-js-sdk@5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/matrix-js-sdk/-/matrix-js-sdk-5.0.0.tgz#dcbab35f1afdb35ef0364eb232e78e0fb7dc2a5b"
+  integrity sha512-A/aeE2Zn2OHq1n/9wIHCszrQZ7oXfThUHWi5Kz7illVCPUJ3JrZ31XVvx02k6vBasDcUtjAfZblHdTVN62cWLw==
   dependencies:
     "@babel/runtime" "^7.8.3"
     another-json "^0.2.0"
@@ -7617,9 +7618,10 @@ matrix-mock-request@^1.2.3:
     bluebird "^3.5.0"
     expect "^1.20.2"
 
-"matrix-react-sdk@github:matrix-org/matrix-react-sdk#develop":
-  version "2.0.0"
-  resolved "https://codeload.github.com/matrix-org/matrix-react-sdk/tar.gz/805e9abb3981584cd941e59c5c10edc3595c38b9"
+matrix-react-sdk@2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/matrix-react-sdk/-/matrix-react-sdk-2.1.0.tgz#60c79b98acfcf5e18534d0fc3ff52ebacb045cfd"
+  integrity sha512-KloXDVtZ1Hy0H1+zVFoZ9+BQlUTYCBVNlxzz2ZQ6T6rZpYOGu7XTLV/i6vaKRvFh+OqVtnF7RS3Z3j0OUqjmzQ==
   dependencies:
     "@babel/runtime" "^7.8.3"
     blueimp-canvas-to-blob "^3.5.0"
@@ -7647,7 +7649,8 @@ matrix-mock-request@^1.2.3:
     is-ip "^2.0.0"
     linkifyjs "^2.1.6"
     lodash "^4.17.14"
-    matrix-js-sdk "github:matrix-org/matrix-js-sdk#develop"
+    matrix-js-sdk "5.0.0"
+    minimist "^1.2.0"
     pako "^1.0.5"
     png-chunks-extract "^1.0.0"
     prop-types "^15.5.8"