Originally Posted by Agama
Calbre is in a constant state of development so there is usually an update once a week: this is a real strength. You are not obliged to install each and every update. Personally I check out what's changed and only get the new version if changes relate to my use of calibre.
You can disable update notifications in Settings > Behaviour. Perhaps there could be another option "Tell me when my version of calibre is obsolete" so that at least this is shown when notifications are off.
My own belief is that Calibre should be like most mainstream programs, and only major updates should come through the alert system automatically. If users are especially technically interested they could then go into the bowels of Calibre and turn that on ....