Hello Ruth,

While I have not done this specific service pack update, it has been my experience that updating service packs on SQL Server is generally safe. It is when you are updating to a whole new version of SQL server where the process need to be treat more like a SQL migration.

~Delray

I assume you've completed the upgrade to SP4, but we are also no doing this and was successful in our test environment and will be applying to production now tonight.