You cant see into the encrypted traffic to see if it's implemented or not.
But in the worst case you'll be able to see that it is plaintext.
Re:The Coder Who Encrypted Your Texts
by em3rgent0rdr on Friday July 10, 2015 @06:07AM
(#9863101)
I would expect any messaging app these days woud never send pafkets with plain text.
Watch the network traffic with Wireshark?