diff --git a/release/adapter.js b/release/adapter.js
index a5ca2f3af..1d001f577 100644
--- a/release/adapter.js
+++ b/release/adapter.js
@@ -101,6 +101,7 @@ function adapterFactory() {
       chromeShim.fixNegotiationNeeded(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimConnectionState(window);
       commonShim.shimMaxMessageSize(window);
       commonShim.shimSendThrowTypeError(window);
       break;
@@ -122,6 +123,7 @@ function adapterFactory() {
       firefoxShim.shimRTCDataChannel(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimConnectionState(window);
       commonShim.shimMaxMessageSize(window);
       commonShim.shimSendThrowTypeError(window);
       break;
@@ -1233,6 +1235,7 @@ var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol
 exports.shimRTCIceCandidate = shimRTCIceCandidate;
 exports.shimMaxMessageSize = shimMaxMessageSize;
 exports.shimSendThrowTypeError = shimSendThrowTypeError;
+exports.shimConnectionState = shimConnectionState;
 
 var _sdp = require('sdp');
 
@@ -1455,6 +1458,67 @@ function shimSendThrowTypeError(window) {
   });
 }
 
+/* shims RTCConnectionState by pretending it is the same as iceConnectionState.
+ * See https://bugs.chromium.org/p/webrtc/issues/detail?id=6145#c12
+ * for why this is a valid hack in Chrome. In Firefox it is slightly incorrect
+ * since DTLS failures would be hidden. See
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=1265827
+ * for the Firefox tracking bug.
+ */
+function shimConnectionState(window) {
+  if (!window.RTCPeerConnection || 'connectionState' in window.RTCPeerConnection.prototype) {
+    return;
+  }
+  var proto = window.RTCPeerConnection.prototype;
+  Object.defineProperty(proto, 'connectionState', {
+    get: function get() {
+      return {
+        completed: 'connected',
+        checking: 'connecting'
+      }[this.iceConnectionState] || this.iceConnectionState;
+    },
+
+    enumerable: true,
+    configurable: true
+  });
+  Object.defineProperty(proto, 'onconnectionstatechange', {
+    get: function get() {
+      return this._onconnectionstatechange || null;
+    },
+    set: function set(cb) {
+      if (this._onconnectionstatechange) {
+        this.removeEventListener('connectionstatechange', this._onconnectionstatechange);
+        delete this._onconnectionstatechange;
+      }
+      if (cb) {
+        this.addEventListener('connectionstatechange', this._onconnectionstatechange = cb);
+      }
+    },
+
+    enumerable: true,
+    configurable: true
+  });
+
+  ['setLocalDescription', 'setRemoteDescription'].forEach(function (method) {
+    var origMethod = proto[method];
+    proto[method] = function () {
+      if (!this._connectionstatechangepoly) {
+        this._connectionstatechangepoly = function (e) {
+          var pc = e.target;
+          if (pc._lastConnectionState !== pc.connectionState) {
+            pc._lastConnectionState = pc.connectionState;
+            var newEvent = new Event('connectionstatechange', e);
+            pc.dispatchEvent(newEvent);
+          }
+          return e;
+        };
+        this.addEventListener('iceconnectionstatechange', this._connectionstatechangepoly);
+      }
+      return origMethod.apply(this, arguments);
+    };
+  });
+}
+
 },{"./utils":15,"sdp":17}],7:[function(require,module,exports){
 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
diff --git a/release/adapter_no_edge.js b/release/adapter_no_edge.js
index 716e01b14..110a2351b 100644
--- a/release/adapter_no_edge.js
+++ b/release/adapter_no_edge.js
@@ -101,6 +101,7 @@ function adapterFactory() {
       chromeShim.fixNegotiationNeeded(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimConnectionState(window);
       commonShim.shimMaxMessageSize(window);
       commonShim.shimSendThrowTypeError(window);
       break;
@@ -122,6 +123,7 @@ function adapterFactory() {
       firefoxShim.shimRTCDataChannel(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimConnectionState(window);
       commonShim.shimMaxMessageSize(window);
       commonShim.shimSendThrowTypeError(window);
       break;
@@ -1233,6 +1235,7 @@ var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol
 exports.shimRTCIceCandidate = shimRTCIceCandidate;
 exports.shimMaxMessageSize = shimMaxMessageSize;
 exports.shimSendThrowTypeError = shimSendThrowTypeError;
+exports.shimConnectionState = shimConnectionState;
 
 var _sdp = require('sdp');
 
@@ -1455,6 +1458,67 @@ function shimSendThrowTypeError(window) {
   });
 }
 
+/* shims RTCConnectionState by pretending it is the same as iceConnectionState.
+ * See https://bugs.chromium.org/p/webrtc/issues/detail?id=6145#c12
+ * for why this is a valid hack in Chrome. In Firefox it is slightly incorrect
+ * since DTLS failures would be hidden. See
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=1265827
+ * for the Firefox tracking bug.
+ */
+function shimConnectionState(window) {
+  if (!window.RTCPeerConnection || 'connectionState' in window.RTCPeerConnection.prototype) {
+    return;
+  }
+  var proto = window.RTCPeerConnection.prototype;
+  Object.defineProperty(proto, 'connectionState', {
+    get: function get() {
+      return {
+        completed: 'connected',
+        checking: 'connecting'
+      }[this.iceConnectionState] || this.iceConnectionState;
+    },
+
+    enumerable: true,
+    configurable: true
+  });
+  Object.defineProperty(proto, 'onconnectionstatechange', {
+    get: function get() {
+      return this._onconnectionstatechange || null;
+    },
+    set: function set(cb) {
+      if (this._onconnectionstatechange) {
+        this.removeEventListener('connectionstatechange', this._onconnectionstatechange);
+        delete this._onconnectionstatechange;
+      }
+      if (cb) {
+        this.addEventListener('connectionstatechange', this._onconnectionstatechange = cb);
+      }
+    },
+
+    enumerable: true,
+    configurable: true
+  });
+
+  ['setLocalDescription', 'setRemoteDescription'].forEach(function (method) {
+    var origMethod = proto[method];
+    proto[method] = function () {
+      if (!this._connectionstatechangepoly) {
+        this._connectionstatechangepoly = function (e) {
+          var pc = e.target;
+          if (pc._lastConnectionState !== pc.connectionState) {
+            pc._lastConnectionState = pc.connectionState;
+            var newEvent = new Event('connectionstatechange', e);
+            pc.dispatchEvent(newEvent);
+          }
+          return e;
+        };
+        this.addEventListener('iceconnectionstatechange', this._connectionstatechangepoly);
+      }
+      return origMethod.apply(this, arguments);
+    };
+  });
+}
+
 },{"./utils":11,"sdp":13}],7:[function(require,module,exports){
 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
diff --git a/release/adapter_no_edge_no_global.js b/release/adapter_no_edge_no_global.js
index 42c0ca786..49780f3f9 100644
--- a/release/adapter_no_edge_no_global.js
+++ b/release/adapter_no_edge_no_global.js
@@ -101,6 +101,7 @@ function adapterFactory() {
       chromeShim.fixNegotiationNeeded(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimConnectionState(window);
       commonShim.shimMaxMessageSize(window);
       commonShim.shimSendThrowTypeError(window);
       break;
@@ -122,6 +123,7 @@ function adapterFactory() {
       firefoxShim.shimRTCDataChannel(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimConnectionState(window);
       commonShim.shimMaxMessageSize(window);
       commonShim.shimSendThrowTypeError(window);
       break;
@@ -1233,6 +1235,7 @@ var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol
 exports.shimRTCIceCandidate = shimRTCIceCandidate;
 exports.shimMaxMessageSize = shimMaxMessageSize;
 exports.shimSendThrowTypeError = shimSendThrowTypeError;
+exports.shimConnectionState = shimConnectionState;
 
 var _sdp = require('sdp');
 
@@ -1455,6 +1458,67 @@ function shimSendThrowTypeError(window) {
   });
 }
 
+/* shims RTCConnectionState by pretending it is the same as iceConnectionState.
+ * See https://bugs.chromium.org/p/webrtc/issues/detail?id=6145#c12
+ * for why this is a valid hack in Chrome. In Firefox it is slightly incorrect
+ * since DTLS failures would be hidden. See
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=1265827
+ * for the Firefox tracking bug.
+ */
+function shimConnectionState(window) {
+  if (!window.RTCPeerConnection || 'connectionState' in window.RTCPeerConnection.prototype) {
+    return;
+  }
+  var proto = window.RTCPeerConnection.prototype;
+  Object.defineProperty(proto, 'connectionState', {
+    get: function get() {
+      return {
+        completed: 'connected',
+        checking: 'connecting'
+      }[this.iceConnectionState] || this.iceConnectionState;
+    },
+
+    enumerable: true,
+    configurable: true
+  });
+  Object.defineProperty(proto, 'onconnectionstatechange', {
+    get: function get() {
+      return this._onconnectionstatechange || null;
+    },
+    set: function set(cb) {
+      if (this._onconnectionstatechange) {
+        this.removeEventListener('connectionstatechange', this._onconnectionstatechange);
+        delete this._onconnectionstatechange;
+      }
+      if (cb) {
+        this.addEventListener('connectionstatechange', this._onconnectionstatechange = cb);
+      }
+    },
+
+    enumerable: true,
+    configurable: true
+  });
+
+  ['setLocalDescription', 'setRemoteDescription'].forEach(function (method) {
+    var origMethod = proto[method];
+    proto[method] = function () {
+      if (!this._connectionstatechangepoly) {
+        this._connectionstatechangepoly = function (e) {
+          var pc = e.target;
+          if (pc._lastConnectionState !== pc.connectionState) {
+            pc._lastConnectionState = pc.connectionState;
+            var newEvent = new Event('connectionstatechange', e);
+            pc.dispatchEvent(newEvent);
+          }
+          return e;
+        };
+        this.addEventListener('iceconnectionstatechange', this._connectionstatechangepoly);
+      }
+      return origMethod.apply(this, arguments);
+    };
+  });
+}
+
 },{"./utils":11,"sdp":13}],7:[function(require,module,exports){
 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
diff --git a/release/adapter_no_global.js b/release/adapter_no_global.js
index e270bedcd..e1f519f82 100644
--- a/release/adapter_no_global.js
+++ b/release/adapter_no_global.js
@@ -101,6 +101,7 @@ function adapterFactory() {
       chromeShim.fixNegotiationNeeded(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimConnectionState(window);
       commonShim.shimMaxMessageSize(window);
       commonShim.shimSendThrowTypeError(window);
       break;
@@ -122,6 +123,7 @@ function adapterFactory() {
       firefoxShim.shimRTCDataChannel(window);
 
       commonShim.shimRTCIceCandidate(window);
+      commonShim.shimConnectionState(window);
       commonShim.shimMaxMessageSize(window);
       commonShim.shimSendThrowTypeError(window);
       break;
@@ -1233,6 +1235,7 @@ var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol
 exports.shimRTCIceCandidate = shimRTCIceCandidate;
 exports.shimMaxMessageSize = shimMaxMessageSize;
 exports.shimSendThrowTypeError = shimSendThrowTypeError;
+exports.shimConnectionState = shimConnectionState;
 
 var _sdp = require('sdp');
 
@@ -1455,6 +1458,67 @@ function shimSendThrowTypeError(window) {
   });
 }
 
+/* shims RTCConnectionState by pretending it is the same as iceConnectionState.
+ * See https://bugs.chromium.org/p/webrtc/issues/detail?id=6145#c12
+ * for why this is a valid hack in Chrome. In Firefox it is slightly incorrect
+ * since DTLS failures would be hidden. See
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=1265827
+ * for the Firefox tracking bug.
+ */
+function shimConnectionState(window) {
+  if (!window.RTCPeerConnection || 'connectionState' in window.RTCPeerConnection.prototype) {
+    return;
+  }
+  var proto = window.RTCPeerConnection.prototype;
+  Object.defineProperty(proto, 'connectionState', {
+    get: function get() {
+      return {
+        completed: 'connected',
+        checking: 'connecting'
+      }[this.iceConnectionState] || this.iceConnectionState;
+    },
+
+    enumerable: true,
+    configurable: true
+  });
+  Object.defineProperty(proto, 'onconnectionstatechange', {
+    get: function get() {
+      return this._onconnectionstatechange || null;
+    },
+    set: function set(cb) {
+      if (this._onconnectionstatechange) {
+        this.removeEventListener('connectionstatechange', this._onconnectionstatechange);
+        delete this._onconnectionstatechange;
+      }
+      if (cb) {
+        this.addEventListener('connectionstatechange', this._onconnectionstatechange = cb);
+      }
+    },
+
+    enumerable: true,
+    configurable: true
+  });
+
+  ['setLocalDescription', 'setRemoteDescription'].forEach(function (method) {
+    var origMethod = proto[method];
+    proto[method] = function () {
+      if (!this._connectionstatechangepoly) {
+        this._connectionstatechangepoly = function (e) {
+          var pc = e.target;
+          if (pc._lastConnectionState !== pc.connectionState) {
+            pc._lastConnectionState = pc.connectionState;
+            var newEvent = new Event('connectionstatechange', e);
+            pc.dispatchEvent(newEvent);
+          }
+          return e;
+        };
+        this.addEventListener('iceconnectionstatechange', this._connectionstatechangepoly);
+      }
+      return origMethod.apply(this, arguments);
+    };
+  });
+}
+
 },{"./utils":15,"sdp":17}],7:[function(require,module,exports){
 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.