Trying to detect if migration to dependency based boot will fail:
WARNING: Removed, but configured, package fetchmail left /etc/init.d/fetchmail behind
[…]
Aborting, because the update would likely fail.
Please check and fix the aforementioned issues.
(To ignore, set the UCRV variable update42/ignore_insserv to yes)
Error: Update aborted by pre-update script of release 4.2-0
WARNING: Removed, but configured, package fetchmail left /etc/init.d/fetchmail behind
This issue should be checked and fixed