T22P massive lag

[Zeon]

Hey all,
We have recently upgraded our T22P's to 7.73.0.40. The support desk is gettign about 10 complaints a day from users who are experiencing lag in the phone. This may include:

• The screen lagging after button press
• Lag on picking up the reeiver to phone actually detecting this and sound coming in on the receiver
• The phone never detecting the receiver was picked up and keeps ringing
  

I'm probably going to downgreade back to v72.

Has anyone else had this issue? We are using Asterisk 1.8 and the old style of CFG fields for autoprovisioning so not sure if that has an impact?