Those following recent posts on the subject will know that you can now install on Ubuntu with,

sudo snap refresh
sudo snap install boinc --beta

This currently installs 8.2.2

replace beta with edge and you get the daily alpha build.

Currently at least on my machines this gets back the exit dialogue about stopping running tasks when closing down the manager which I know some of us like.

The only downside I can see is when there is an update, it gets automagically installed by snapd closing down the application after 13 days. (Some tasks I run are prone to crashing on closing down and restarting BOINC.)