 
 class NotificationService: UNNotificationServiceExtension {
     
+    /// Content handlers. Keys are eventId's
     var contentHandlers: [String: ((UNNotificationContent) -> Void)] = [:]
-    var originalContent: UNMutableNotificationContent?
+    
+    /// Original contents. Keys are eventId's
+    var originalContents: [String: UNMutableNotificationContent] = [:]
     
     var cachedEvent: MXEvent?
     var mxSession: MXSession?

        //  close session
        mxSession?.close()
        
        guard let content = originalContent else {
            NSLog("[NotificationService] fallbackToOriginalContent: Original content is missing.")
            return
        }

    }
    
    func fetchEvent(withEventId eventId: String) {
        guard let content = originalContents[eventId], let mxSession = mxSession else {
            //  there is something wrong, do not change the content
            NSLog("[NotificationService] fetchEvent: Either originalContent or mxSession is missing.")
            fallbackToOriginalContent(forEventId: eventId)
