A proof of concept email (JMAP) client currently in development. It makes heavy use of Android Jetpack for a more maintainable code base than some of the preexisting Android email clients.
Ltt.rs is based on jmap-mua which is basically a headless email client or a library that handles everything an email client would aside from data storage and UI. There is also lttrs-cli which uses the same library.
At this stage of development trying it means compiling and setting up the latest development version of Cyrus and then putting your credentials into Credentials.java.