You can check the current PostgreSQL version in several ways depending on whether you’re inside psql, using command line, or checking from SQL.
From SQL (psql shell or any client):
SELECT version();
This gives the full version details (including build info, compiler, and OS).
If you just want the number:
SHOW server_version;
Client version from Command Line:
psql --version
psql -V
From System Package Manager
RHEL/CentOS/Rocky/Alma:
rpm -qa | grep postgres
Debian/Ubuntu:
dpkg -l | grep postgre