Add documentation about setting the log level. #6135
Fixed: don't reset watchers when changing tracker. #6479
Translation updates * pt-BR (#6490)
Project tests updated.
Fixed: gantt broken when no due date on project issues and versions.
Fixed: error on mail notification when adding an invalid file (#6452).
Fixes broken filter clearing links on gantt and calendar (#6473).
Translation updates * cs (#6471)
Refactor: move NewsController#preview to PreviewsController#news
Translation updates * cs (#6471) * ja (#6465) * zh-TW (#6466)