T21P and 3cx 15.5U6

[GSSOAZ_Admin]

Hello. I have 3cx (15.5U3) installed on a Windows 2012 R2 Server. I also have about 16 Yealink T21P phones I am currently using. I know these phones are end of life but I was wondering if there are any issues with the T21P phones when updating to 15.5U6 from U3.Are there any precautions I should take when upgrading the system with respect to the T21P phones.

 

[Saqqara]

You need to upgrade to v16 update 5 https://www.3cx.com/blog/releases/remote-working-video-app/ , as 15.5 reaches eol on 1st June 2020

if you use iOS devices you have to upgrade https://www.3cx.com/blog/releases/apple-push-update-windows/

your biggest issue is that windows server 2012 is not supported for version 16 , see https://www.3cx.com/docs/manual/phone-system-installation-windows/ for supported operating systems or the other option is to use Debian

info on upgrading https://www.3cx.com/docs/upgrading-pbx-v16/

going back to your question t21p phones are still 3cx supported https://www.3cx.com/sip-phones/yealink-t20p-t22p-t26p-t28p/