Legacy Database Compatibility Level

This warning indicates that the database is not running with the latest compatibility level that the SQL Server version supports. Using the highest compatibility level enables your instance to take advantage of the latest features and database engine improvements.

For example, this could mean the database is using compatibility level 110 (SQL Server 2012), but the instance is SQL Server is 2019. Using lower compatibility levels may be a requirement, but if not, there could be enhanced or new features that your systems could be using.

Suggested Action

Aim to use the highest database compatibility level the server can support.

How to Set the Database Compatibility Level in SQL Server

SET COMPATIBILITY_LEVEL = { 150 | 140 | 130 | 120 | 110 | 100 | 90 }

Further Reading

View or Change the Compatibility Level of a Database | Microsoft Docs

ALTER DATABASE (Transact-SQL) Compatibility Level | Microsoft Docs