libsignal VS textsecure

I am in the process of building a Go implementation of the libsignal-protocol, which powers the Signal app.

How is twitter intending to use libsignal? I doubt it would be via the primary AGPL license[1], forcing them to publish the source code of their server source code. Does signal sell private licenses?

[1] https://github.com/signalapp/libsignal/blob/main/LICENSE

The Signal Protocol is licensed under AGPLv3 (see here).

Signal protocol is AGPL3 https://github.com/signalapp/libsignal

This is the license for libsignal: https://github.com/signalapp/libsignal/blob/main/LICENSE

The only reference to trademark is:

> Notwithstanding any other provision of this License, for material you add to a covered work, you may (if authorized by the copyright holders of that material) supplement the terms of this License with terms:

I can't vouch for it, but this looks worth checking out: https://github.com/signal-golang/textsecure

So I think we need a native Linux client. I do not think Axolotl is a viable long term solution because it uses its own implementation of the Signal network protocol (written in Go). Reimplementing the cryptography and network protocol is a ton of work and will continue to be a ton of work as upstream adds more features. Axolotl has only just started reimplementing the new Signal groups protocol which was introduced 5 months ago. Also, the security of a reimplementation is dubious.