If you're going to install the latest version of FNMS (that is, change the version that you currently have), you'll need to migrate the databases to match the FNMS version first, even if you're not changing their location. So in essence you will be changing the databases.
If you install the same version of FNMS that you currently have, then you shouldn't need to perform any database migration.
In either case, the Powershell configuration script will allow you to restore the database connection.
Depending on how far back your current version of FNMS is from the latest version, you could run into a "Could not load file or assembly 'sqlproceduresclr" issue when migrating your Compliance database. See https://community.flexera.com/t5/FlexNet-Manager-Forum/Compliance-Database-Upgrade-Error-Could-Not-Load-Assembly-quot/m-p/259368#M16565 and https://community.flexera.com/t5/FlexNet-Manager-Suite-Known/Known-Issue-Database-migration-may-fail-if-database-is-restored/ta-p/260837.
