The current list of bugs and feature requests is in the issue tracker:
There are two ways you can report a bug or request a feature. The preferred way is by going directly to the reporting system:
For Monal: http://redmine.monal.im/projects/monal/issues/new
For Sleeptrack: http://redmine.monal.im/projects/sleeptrack/issues/new
You do not have to create an account to submit something. However, if you would like to stay notified on the issue or expect to submit more in the future, I would recommend creating an account.
Alternatively, you can send an email to bugs@monal.im or on Twitter, @monalxmpp
Thanks!