On Mon 06 Sep 2021 at 08:34:44 -0400, Greg Wooledge wrote: [...]
> Also, there's the wee little fact that testing is no longer a synonym > for bullseye, and therefore even if the fourth one *did* work, it > wouldn't be equivalent to the other three. With only http://security.debian.org bullseye/updates main or http://deb.debian.org bullseye/updates main in sources.list your "even if" is substantiated. root@bullseye:~# apt update E: Type 'http://deb.debian.org' is not known on line 7 in source list /etc/apt/sources.list E: The list of sources could not be read. The updates service has been switched off for bullseye. For all those users who "know what they are doing" when upgrading, this may be seen as a wake-up call. -- Brian.