Can you be on the latest version firmware and downgrade to an older version?

[XSONY_NGUX]

Question is in the title, i need to know this because i want to install a sky skin from the firmware's section but will i be able to if it's on a old version and i'm on a newer version on my box?

Other question is whether i can go from openatv to openvix firmware?

 

[cactikid]

openatv is supported vix is not so would be on older patched images.