The Cheogram Android app allows you to join a worldwide communication network. It especially focuses on features useful to users who want to contact those on other networks as well, such as SMS-enabled phone numbers.
Based on the app Conversations, but with unique features:
If you have code or patches you wish to contribute, the maintainer's preferred mechanism is a git pull request. Push your changes to a git repository somewhere, for example:
git remote rename origin upstream
git remote add origin email@example.com:~yourname/cheogram-android
git push -u origin master
Then generate the pull request:
git fetch upstream master
git request-pull -p upstream/master origin
And copy-paste the result into a plain-text email to: firstname.lastname@example.org
You may alternately use a patch-based approach as described on https://git-send-email.io
Contributions follow an inbound=outbound model -- you (or your employer) keep all copyright on your patches, but agree to license them according to this project's COPYING file.