diff --git a/SocketIOClientSwift/SocketPacket.swift b/SocketIOClientSwift/SocketPacket.swift
index 9a9889c..a8b44d3 100644
--- a/SocketIOClientSwift/SocketPacket.swift
+++ b/SocketIOClientSwift/SocketPacket.swift
@@ -289,9 +289,9 @@ private extension SocketPacket {
             }
             
             return arr
-        } else if var dict = data as? [String: AnyObject] {
+        } else if let dict = data as? NSMutableDictionary {
             for (key, value) in dict {
-                dict[key] = shred(value, binary: &binary)
+                dict[key as! NSCopying] = shred(value, binary: &binary)
             }
             
             return dict