F5 Software Upgrade from 10.2 to 12.1.2

Hi,

 

we needs to upgrade F5 Cluster from existing 10.2 version to 12.1.2 version.Is there any document I needs to follow for upgrade steps from 10.2 to 12.1.2.

 

Can I go directly or first needs to upgrade to 11 series and then from 11.X to 12.1.2