snort version on device is out of date

[network1215]

I am trying to push software update to FTDs from FMC FMC running 6.6.1 version and same version trying to push on FTD but it gives error message. 

Pre upgrade validation - snort version on device is out of date. Deploy access control policy from FMC and trigger upgrade. Device state is not changed.

Any clue what this is ? 

[Marvin Rhoads]

Just what the message says. You cannot upgrade if the managed device is too far out of date from the FMC with its Snort rule updates (SRU). The SRU version is synced any time you do a deployment. If you have no other changes pending, you can do something minor like add a comment in the Access Control Policy title and then save and deploy to force a SRU sync.