I saw the client in sort like minecraft's client I had no idea they now placed a restriction. I believe this may be a an occasional announcement. IMVU will subtly raise the client versions acceptable and appropriate for use and therefore connection to the servers. Any older clients will be eventually phased out as newer clients take over from older ones. I think its necessary, as they will not have to work on supporting older versions as well as their mainstream version. And the immediate versions below or above (experimental/test).