Requires either removing stage feature or stabilisation of slot 5.
Is there any reason to not stabilise slot 5?
Originally we wanted to wait for 3.1 to be a full replacement for 2.9 (translations, braindump, stage) but it seems that is still going to take a long time...
calligra:4 was dropped in git commit 07319fb870a05e878406f2ae5ab497f87468306c.