My name is Contara from Zerto Support.
Zerto uses a modified form of SQL under hidden directories (show hidden files)
You can point to a external SQL server or migrate to it using document
Migrating the ZVM Database to SQL Server – Zerto Software
See pages 6 and 7 of Zerto Scale and Benchmarking Guidelines
To see when you might need an External DB
is it possible to upgrade SQL then? i’m having an issue where the version of SQL on the zvm server is older
Yes, you can upgrade the SQL server. Please be sure to save/protect the ZVM DB file while doing that.