diff --git a/src/components/views/dialogs/CreateGroupDialog.js b/src/components/views/dialogs/CreateGroupDialog.js
index bda298ef0b..12f419ddd6 100644
--- a/src/components/views/dialogs/CreateGroupDialog.js
+++ b/src/components/views/dialogs/CreateGroupDialog.js
@@ -55,8 +55,8 @@ export default React.createClass({
 
     _checkGroupId: function(e) {
         let error = null;
-        if (!/^[a-zA-Z0-9]*$/.test(this.state.groupId)) {
-            error = _t("Community IDs may only contain alphanumeric characters");
+        if (!/^[a-z0-9=_\-\.\/]*$/.test(this.state.groupId)) {
+            error = _t("Community IDs may only contain characters a-z, 0-9, or '=_-./'");
         }
         this.setState({
             groupIdError: error,
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index a541e9e130..bffe3b3264 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -152,7 +152,6 @@
     "%(widgetName)s widget removed by %(senderName)s": "%(widgetName)s widget removed by %(senderName)s",
     "Communities": "Communities",
     "Message Pinning": "Message Pinning",
-    "Mention": "Mention",
     "%(displayName)s is typing": "%(displayName)s is typing",
     "%(names)s and one other are typing": "%(names)s and one other are typing",
     "%(names)s and %(count)s others are typing|other": "%(names)s and %(count)s others are typing",
@@ -240,6 +239,7 @@
     "Unignore": "Unignore",
     "Ignore": "Ignore",
     "Jump to read receipt": "Jump to read receipt",
+    "Mention": "Mention",
     "Invite": "Invite",
     "User Options": "User Options",
     "Direct chats": "Direct chats",
@@ -488,6 +488,7 @@
     "Identity server URL": "Identity server URL",
     "What does this mean?": "What does this mean?",
     "Remove from community": "Remove from community",
+    "Failed to withdraw invitation": "Failed to withdraw invitation",
     "Failed to remove user from community": "Failed to remove user from community",
     "Filter community members": "Filter community members",
     "Filter community rooms": "Filter community rooms",
@@ -588,7 +589,7 @@
     "Confirm Removal": "Confirm Removal",
     "Are you sure you wish to remove (delete) this event? Note that if you delete a room name or topic change, it could undo the change.": "Are you sure you wish to remove (delete) this event? Note that if you delete a room name or topic change, it could undo the change.",
     "%(actionVerb)s this person?": "%(actionVerb)s this person?",
-    "Community IDs may only contain alphanumeric characters": "Community IDs may only contain alphanumeric characters",
+    "Community IDs may only contain characters a-z, 0-9, or '=_-./'": "Community IDs may only contain characters a-z, 0-9, or '=_-./'",
     "Something went wrong whilst creating your community": "Something went wrong whilst creating your community",
     "Create Community": "Create Community",
     "Community Name": "Community Name",