Phone book problems on Yealink T21P E2

[bytesolutions]

Good morning everyone.
I recently activated a 3CX v18 Update 6 system with a customer who already had about 20 Yealink T21P E2 already purchased.
I avoided having them replace them, so I simply updated them with the firmware version on the 3CX website (v. 52.84.0.140) and auto-provisioned them.
They work perfectly, but I'm having a problem in the 3CX directory.
The address book is displayed correctly, and it is possible to make calls, but it is not possible to add a new contact from the phone, in fact the "add" item (which is present in the local phone book) is not present at all.
Is it possible to solve it in some way or is it a limitation of the telephone and do I have to let the customer manage the address book via the web interface?
Thank you

 

[Charles_3CX]

You should not add contacts directly to the IP phones. Using the Mobile number field within the company phonebook, you can populate the 3cx remote phonebook within the IP phones. Also, update the system to the latest supported version of update 7, where you can provision these IP phones.