• [X ] This is not a feature request (existing functionality does not work, not missing functionality).
  I will request features on forum or via support.
• [ X] I've searched and did not find a similar issue.

Describe the bug
We have received a report from a member of our Belarusian translation team and they are nearing the completion of their project.

Please fix issues with the Belarusian language in the app:

• if I send an encrypted email to an outside recipient and choose Belarusian as notification language, the email comes in English, not in Belarusian (Linux, Android, Web).
• the calendar dates in Email and Calendar are shown in English, not in Belarusian (on Linux, Windows and Android; but on Web App it works well)