Hi, Another interesting observation. After upgrading galera-3 from buster to bullseye first, apt will install 10.5..
# apt full-upgrade The following packages will be REMOVED: libpython-stdlib mariadb-client-10.3 mariadb-client-core-10.3 mariadb-server mariadb-server-10.3 mariadb-server-core-10.3 python python-minimal The following packages will be upgraded: galera-3 libpython2-stdlib libpython2.7-minimal libpython2.7-stdlib python2 python2-minimal python2.7 python2.7-minimal 8 upgraded, 0 newly installed, 8 to remove and 0 not upgraded. # apt install galera-3 The following packages will be upgraded: galera-3 1 upgraded, 0 newly installed, 0 to remove and 8 not upgraded. # apt full-upgrade The following packages will be REMOVED: galera-3 libpython-stdlib mariadb-client-10.3 mariadb-client-core-10.3 mariadb-server-10.3 mariadb-server-core-10.3 python python-minimal The following NEW packages will be installed: galera-4 mariadb-client-10.5 mariadb-client-core-10.5 mariadb-server-10.5 mariadb-server-core-10.5 The following packages will be upgraded: libpython2-stdlib libpython2.7-minimal libpython2.7-stdlib mariadb-server python2 python2-minimal python2.7 python2.7-minimal 8 upgraded, 5 newly installed, 8 to remove and 0 not upgraded.