2022-02-11 00:49:45.508 CET   [20205]FATAL:  database files are incompatible with server
2022-02-11 00:49:45.508 CET   [20205]DETAIL:  The data directory was initialized by PostgreSQL version 13, which is not compatible with this version 14.1.

ls /var/lib/pgsql/data
PG_VERSION            log/                  pg_ident.conf         pg_replslot/          pg_stat_tmp/          pg_wal/               postmaster.opts       
base/                 pg_commit_ts/         pg_logical/           pg_serial/            pg_subtrans/          pg_xact/              postmaster.pid        
current_logfiles      pg_dynshmem/          pg_multixact/         pg_snapshots/         pg_tblspc/            postgresql.auto.conf  
global/               pg_hba.conf           pg_notify/            pg_stat/              pg_twophase/          postgresql.conf

# remove the directory if it contains files like these

rapthalia:/etc # su -l postgres -s /bin/bash
postgres@rapthalia:~> postgres
postgres: could not access directory "/var/lib/pgsql/data": No such file or directory
Run initdb or pg_basebackup to initialize a PostgreSQL data directory.
postgres@rapthalia:~> initdb 
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 database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

creating directory /var/lib/pgsql/data ... 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/Bratislava
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

initdb: warning: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success. You can now start the database server using:

    pg_ctl -D /var/lib/pgsql/data -l logfile start