Chats: hide read receipts for unsupported servers

app/soapbox/features/chats/components/chat-message-list.tsx

@@ -348,7 +348,7 @@ const ChatMessageList: React.FC<IChatMessageList> = ({ chat }) => {
                   {intl.formatTime(chatMessage.created_at)}
                 </Text>
 
-                {isMyMessage ? (
+                {(isMyMessage && features.chatsReadReceipts) ? (
                   <>
                     {isRead ? (
                       <span className='rounded-full flex flex-col items-center justify-center p-0.5 bg-primary-500 text-white dark:bg-primary-400 dark:text-primary-900 border border-solid border-primary-500 dark:border-primary-400'>

app/soapbox/utils/features.ts

@@ -238,6 +238,12 @@ const getInstanceFeatures = (instance: Instance) => {
      */
     chatsMedia: v.software !== TRUTHSOCIAL,
 
+    /**
+     * Whether chat messages have read receipts.
+     * @see GET /api/v1/pleroma/chats/:id/messages
+     */
+    chatsReadReceipts: v.software === TRUTHSOCIAL,
+
     /**
      * Ability to search among chats.
      * @see GET /api/v1/pleroma/chats