I've run the server source as a private textsecure chat app. You can run your own without the proprietary gapps framework app too by mimicking what GCM does on

I've run the server source as a private textsecure chat app. You can run your own without the proprietary gapps framework app too by mimicking what GCM does on your own back end, and it works with wifi if you change the identifiers to email/nicks instead of phone numbers, but this was for a small number of coworkers nothing of massive scale. This was for business communication from China since at that time TS wasn't working very well behind the GFC but they added another server around that time (I assume, all connections got better) so we abandoned our hacked fork for regular TS/Signal.