App maintenance
- Android 4.x support has been dropped. As a consequence, the app's download size is reduced by 40%! (#2031), thanks @Isira-Seneviratne
- Translator credits are now generated automatically (#3214)
- The uploading of changes will now never be cancelled by the Android system after the app has been sent to the background for a while (#3279)
- Various code maintenance and refactorings (#3274, #3223, #3259, #3273, #3296, #2894, ...), thanks @sumanabhi, @Isira-Seneviratne, @peternewman, @smichel17