v2.8.0

Added

• Calendars and task lists have an "Allow Editing" switch in their Edit dialog, on Linux and
  Android: turned off, the calendar or list is only shown and its events and tasks cannot be
  changed here, to keep a calendar from being changed by accident. It is on for every calendar
  or list its account lets you change, and off and disabled, with a note, for a read-only one.
  The switch is kept on this device only.

• Android: events of System Calendars (Google, DAVx⁵…) can be added, edited, moved and deleted in
  Todav when the account lets you change that calendar. The change is made in Android's calendar
  store, and the account's own sync (DAVx⁵, Google) uploads it, so no second sign-in is needed.
  Events that repeat, and invitations from somebody else, are still only shown there. Todav asks for the permission to change
  calendars along with the one to read them; Preferences → System Calendars asks again if you
  allowed reading only.