Upgrade von Postgresql 10 auf 12

pg_upgradecluster 10 main
Stopping old cluster...
Restarting old cluster with restricted connections...
Notice: extra pg_ctl/postgres options given, bypassing systemctl for start operation
Creating new PostgreSQL cluster 12/main ...
/usr/lib/postgresql/12/bin/initdb -D /var/lib/postgresql/12/main --auth-local peer --auth-host md5 --encoding UTF8 --lc-collate en_US.UTF-8 --lc-ctype en_US.UTF-8
The files belonging to this database system will be owned by user "postgres".  
This user must also own the server process.

The database cluster will be initialized with locale "en_US.UTF-8".  
The default text search configuration will be set to "english".  

Data page checksums are disabled.

fixing permissions on existing directory /var/lib/postgresql/12/main ... ok
creating subdirectories ... ok
selecting dynamic shared memory implementation ... posix
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting default time zone ... Europe/Berlin
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

Success. You can now start the database server using:

    pg_ctlcluster 12 main start

Ver Cluster Port Status Owner    Data directory              Log file
12  main    5433 down   postgres /var/lib/postgresql/12/main /var/log/postgresql/postgresql-12-main.log

Starting new cluster...
Notice: extra pg_ctl/postgres options given, bypassing systemctl for start operation
Roles, databases, schemas, ACLs...
pg_dump: error: query failed: ERROR:  could not access file "$libdir/postgis-2.4": No such file or directory