I've got a customer with a 670 running AR5.20 MT014.00 software.

They're experiencing some intermittent glitchy problems. Sometimes various extensions will get stuck in something like a permanent call forward to voicemail. Phone is not call forwarded or in DND or anything like that. Nothing I do will fix the problem unless I delete and re-assign the station.

I want to update them to something like MT076 or better. Can I go straight to the newer version or do I need to worry about intermediate updates or anything? They're probably the oldest CIX we're servicing.