18th October 2018: PostgreSQL 11 Released!
Unsupported versions: 7.0 / 6.5 / 6.4

Summary

Postgres, developed originally in the UC Berkeley Computer Science Department, pioneered many of the object-relational concepts now becoming available in some commercial databases. It provides SQL92/SQL3 language support, transaction integrity, and type extensibility. PostgreSQL is an open-source descendant of this original Berkeley code.