Problem
An existing (and edited) squid.conf file got lost during upgrade to UCS 4.3 and was overwritten by a default configuration file from the package. There is no “.debian” or “.dist-upgrade” file at all.
Solution
Step 1
As some changes have happened to the Squid configuration there has been some changes. The previous files have been moved to /etc/squid3-update-4.3. You can copy your modified file from this backup folder.
Step 2
Make sure you have the univention meta package installed in order to have such backup folder in future: univention-install univention-squid (this applies for other packages, too!)
Step 3
Instead of editing the configuration file (which might be overwritten by ucr commit) use a squid.local file to customize your setup.
This file will be read upon start of squid and does not get overwritten on updates.