diff --git a/lib/crypto/OlmDevice.js b/lib/crypto/OlmDevice.js
index ca9565fe3..bca4280ab 100644
--- a/lib/crypto/OlmDevice.js
+++ b/lib/crypto/OlmDevice.js
@@ -578,17 +578,21 @@ OlmDevice.prototype._getInboundGroupSession = function(
  *
  * @param {string} roomId     room in which this session will be used
  * @param {string} senderKey  base64-encoded curve25519 key of the sender
- * @param {string} sessionId  session identifier
  * @param {string} sessionKey base64-encoded secret key at index chainIndex
  * @param {number} chainIndex index at which sessionKey applies
  */
 OlmDevice.prototype.addInboundGroupSession = function(
-    roomId, senderKey, sessionId, sessionKey, chainIndex
+    roomId, senderKey, sessionId, sessionKey, chainIndex,
 ) {
     var self = this;
     var session = new Olm.InboundGroupSession();
     try {
-        session.create(chainIndex, sessionKey);
+        session.create(sessionKey);
+        if (sessionId != session.session_id()) {
+            throw new Error(
+                "Mismatched group session ID from senderKey: " + senderKey
+            );
+        }
         self._saveInboundGroupSession(roomId, senderKey, sessionId, session);
     } finally {
         session.free();
diff --git a/lib/crypto/algorithms/megolm.js b/lib/crypto/algorithms/megolm.js
index b10794524..0a809780a 100644
--- a/lib/crypto/algorithms/megolm.js
+++ b/lib/crypto/algorithms/megolm.js
@@ -124,7 +124,7 @@ MegolmEncryption.prototype._prepareNewSession = function(room) {
 
     this._olmDevice.addInboundGroupSession(
         this._roomId, this._olmDevice.deviceCurve25519Key, session_id,
-        key.key, key.chain_index
+        key.key
     );
 
     // we're going to share the key with all current members of the room,
@@ -394,8 +394,7 @@ MegolmDecryption.prototype.onRoomKeyEvent = function(event) {
 
     if (!content.room_id ||
         !content.session_id ||
-        !content.session_key ||
-        content.chain_index === undefined
+        !content.session_key
        ) {
         console.error("key event is missing fields");
         return;
@@ -403,7 +402,7 @@ MegolmDecryption.prototype.onRoomKeyEvent = function(event) {
 
     this._olmDevice.addInboundGroupSession(
         content.room_id, event.getSenderKey(), content.session_id,
-        content.session_key, content.chain_index
+        content.session_key
     );
 };
 
diff --git a/package.json b/package.json
index a425f13d0..d31ec996d 100644
--- a/package.json
+++ b/package.json
@@ -39,6 +39,6 @@
     "uglifyjs": "^2.4.10"
   },
   "optionalDependencies": {
-    "olm": "https://matrix.org/packages/npm/olm/olm-1.2.0.tgz"
+    "olm": "https://matrix.org/packages/npm/olm/olm-1.3.0.tgz"
   }
 }