Postfix missing after Upgrade to 2.1.1

My postfix is completely goofed after running the 2.1.1 upgrade. I try to start the service and I get this -
Failed to start postfix.service: Unit not found.

Any help would be appreciated

Follow this guide here: Email not working after CyberPanel Upgrade? - CyberPanel

Thank you for replying - this was a fix for the missing postfix and all are working again. I have 6 other servers to update and I am just curious to the developers as to why the postfix got ‘zapped’. I have upgraded from 2.0 to each of the 2.0.x updates - all smooth and all no problems. Thinking there may be something broke or goofed in the 2.1.1 upgrade script from 2.03 or in general? It broke (postfix was gone) on 3 different VPSes on me yesterday. (All are fixed from the instructions - so again thank you!)