We have question about R12.2 Patching

Hi ,

  We have question about R12.2 Patching. We knew that in R12.2 patching has been changed, first we have to apply patches on Patch Edition and resync file patch file system with runtime edition (which is actual file system).

        My question is :

--    Is it mandatory to apply patches first in patch Edition and then resync with runtime edition?

 --    Can we apply patches directly to runtime edition, instead of applying in Patch Edition and then resync with runtime edition (which is actual file system) how we use to apply in R12.1.3?

-- can we apply R12.2 Patches using adop on run time edition directly?