Yes ,this is possible and you do not have to take into account any special action. Only advise to you would be to upgrade to the latest maintenance release for FR26 first and then upgrade to FR28. Have you considered upgrading to FR32 instead of FR28?

B.t.w. not sure if you follow developments, but the version you are currently running is not supported anymore and it also running a near GA build release. This means you are lacking a lot of security updates for the core product, but also for all frameworks that Commvault uses. To keep you environment safe it is recommended to perform frequent update to newer maintenance releases.