You want to upgrade to CCS 12.5.2, and avoid any possible problems during the upgrade.
Upgrading CCS versions CCS 12.5 or CCS 12.5.1 can be directly upgraded to CCS 12.5.2. If you are on 12.0 or 12.0.1 you will need to upgrade to CCS 12.5 first, then upgrade to 12.5.2.