I'm working on my backend app GCM server and from my understanding of the documentation every downstream message my app server sends should receive an ACK if successful or NACK if there's an issue. I'm able to send downstream messages successfully as my app is receiving them, but I never get any ACKs. I tried testing NACKs by putting in a bogus registration ID for when sending a downstream message but still get nothing.
I'm using the smack library and I've tried sending downstream messages with both
XMPPTCPConnection.send()
XMPPTCPConnection.sendStanzaWithResponseCallback()
And neither give a response. Am I missing something?