Challenge
Upgrade to Veeam Backup & Replication 9.5 you receive the error "Unsupported SQL Version"
Cause
If you have a supported database (2008 or newer), the upgrade cannot be installed if the compatibility mode is set to 2005.
Solution
Manually update the compatibility of the VeeamBackup database (or custom named equivalent) via SQL Management Studio or using a query. The compatibility mode must be set to 2008 or newer.
Query:
Alter Database VeeamBackup set compatibility_level = 100
UI:
1. Connect to instance via SSMS
2. Right-click Veeam Database -> Properties
3. Select Options
4. Select Compatibility Level
5. Set to 2008, 2012, 2014 or 2016.