Sorry for my absence, I haven't forgot the project, just stashed for a while.

Some updates on what I've done so far:
The official libraries provided by telegram are in java, but java isn't the ideal language to develop this project on maemo. This telegram client that I managed to compile is not meant to be a library so is not quite straightforward to reuse the code. I've made some tweaks to this telegram client and I been able to use it as a library in a Qt C++ project, and show a list of contacts in a gui, but only that for now. As soon as this project takes shape I'll upload the code to github, meanwhile it's just too messy to share.