Cisco 8800 phone replacements - PIN needed

[Eve M]

We recently upgraded to CUCM 12.5 and there are differences when replacing phone sets to new models.  I have many Cisco 8800 sets programmed in CUCM and some of them, when booting up, are asking for a primary extension and PIN.  I have added PIN's to some (under end user config) and the new phone accepts it but have a handful that are not accepting the PIN.  

Not sure what the issue is.  Each of these users have a phone associated with it.

Thank you.

[Nithin Eluvathingal]

It's not an issue its the  phone refresh feature introduced with 12.5 SU(3). you can replace existing old phones with new and its an easy process. 

Refer the below video.

https://www.youtube.com/watch?v=A_Cila92cNQ