Check your databases are in the correct version

DECLARE @ver nvarchar(128)
SET @ver = CAST(serverproperty('ProductVersion') AS nvarchar)
SET @ver = SUBSTRING(@ver, 1, CHARINDEX('.', @ver) - 1)

SELECT
[name] AS DatabaseName ,
200 AS Priority ,
'Performance' AS FindingsGroup ,
'Old Compatibility Level' AS Finding ,

( 'Database ' + [name]
 + ' is compatibility level '
 + CAST(compatibility_level AS VARCHAR(20))






 + ', which may cause unwanted results when trying to run queries that have newer T-SQL features.' ) AS Details
FROM    sys.databases


where
   CASE compatibility_level
    WHEN 65  THEN '6'
    WHEN 70  THEN '7'
    WHEN 80  THEN '8'
    WHEN 90  THEN '9'
    WHEN 100 THEN '10'
    WHEN 110 THEN '11'
    WHEN 120 THEN '12'
    end

    <>   @ver

Nice case to work out the SQL version from the product level.

CASE compatibility_level
    WHEN 65  THEN 'SQL Server 6.5'
    WHEN 70  THEN 'SQL Server 7.0'
    WHEN 80  THEN 'SQL Server 2000'
    WHEN 90  THEN 'SQL Server 2005'
    WHEN 100 THEN 'SQL Server 2008/R2'
    WHEN 110 THEN 'SQL Server 2012'
    WHEN 120 THEN 'SQL Server 2014'