Fixes a crash on start on older Android versions: the app could ask the system to fill a field before that field had been placed on screen, which Android refuses. It also fixes several places where a message was identified by its id alone. Message ids are handed out per account, so with more than one account on the same server two different messages can carry the same id, and the app could open the wrong one, let a notification's Mark read, Delete or Reply act on the other account's message, or fail to list a search result. Elsewhere: the OpenPGP settings say more plainly what they do, and Drafts and Sent no longer offer "Mark all read", where nothing is unread anyway.
