Hi @HitenBhavsar-MSFT Thank you for your query.
Flexible Server supports for now PostgreSQL versions 11.14, 12.9, and 13.5 on Azure Database for PostgreSQL.
The current minor release is 13.6. Refer to the PostgreSQL documentation to learn more about improvements and fixes in this release.
Postgres version 14 is not yet available, we don't have a road map or timelines when it will be available.