@playforvoices I think not. I did not research Deltachat, but we had a thread on Threema before and someone reported having run OpenMittsu on Libertine, but it isn't very practical.

But OpenMittsu has a desktop Qt based (bad) UI and I am sure the main developer would highly apprechiate someone contributing a more modern QtQuick based UI also compatible with UT.

Otherwise... the Threema web client is open source and should be fairly easy to get running as a Webapp on UT. However similar to WhatsApp web it needs a running Android or iOS client to relay the messages.