Spark responds differently based on which two versions are interacting

Has anyone noticed any quirks when two different versions of spark are running that respond differently based on which two versions are running?

One that I have noticed so far is:

About half of the computers on our network are running version 1.1.1 and the other half are running 1.1.4.

If I log into spark twice using two 1.1.4 systems, both logins will remain online, and whichever one I had a chat room open in last will be the client that receives messages.

If I log into spark twice using a 1.1.1 system and a 1.1.4 system, I get disconnected from the computer I was logged into first.

I also get logged out if I log into two systems that both run 1.1.1.

I haven’'t played around with talking between two versions of clients to see any other discrepancies yet.