Debian GNU/Linux 11 (bullseye) was released 14 August 2021. I have upgraded 3 servers to the latest version and the upgrade experience has been quite smooth. The one thing which is missing from the Debian upgrade instructions is the security updates line for bullseye in sources.list. Normally, you would have the following line in your /etc/apt/sources.list
deb http://security.debian.org/debian-security stretch/updates main
Change it to the following before doing apt update:
deb http://security.debian.org/debian-security bullseye-security main
Ref: Debian 11 Errata
