GPL might hinder adoption
I understand that ChatSecure generally puts everything out under the GPL, however I wonder whether the push client lib is intended to aim for broader adoption compared to stronger protection of end-user rights. Projects for whom GPL is not an option are likely to either write a client under more permissive licenses, or look for different push server infrastructure.
If the ChatSecure license people are aware of this consideration and have decided that it's a good trade-off for this SDK (and the Android one, I guess) then feel free to close this issue.
I was actually planning on using a different license, looks like this is just a placeholder for now. I will probably settle on MPL 2.0, which is a weak copyleft license similar to LGPL.