As you know, Trimble Positions Desktop add-in stores projects and sessions in a database that we keep "behind the scenes" as much as possible. When you first installed the software, you would have used the Desktop Configuration application to create a new database configuration. This is typically a Jet (.mdb) or SQLite (if you installed the drivers) database, but can generally be any ODBC database connection that you've defined. This database has a schema (set of tables) that does get updated periodically as we develop new functionality that requires it. In previous versions of the software when we made a schema change, we required you to use the Desktop Configuration application to first update the schema by clicking the Test configuration link.
As a result of this requirement, we had recommended a "best practice" to be running the Desktop Configuration application after every upgrade just to validate and update the schema if necessary.
Starting at Trimble Positions Desktop add-in 10.8.0.1, this is no longer strictly necessary. The add-in itself will now self-update the database schema if required by that new version. You will be notified of the schema upgrade requirement the first time you run ArcGIS Desktop with the new version of the add-in loaded. You do have the option to not proceed with the schema upgrade if you would prefer to make a backup copy of the database first. This may be useful in situations where you anticipate a need to rollback to a previous version.
As a reminder, your project data will not be affected during these schema upgrades.