Not informed of the change
I just got massively caught out by this change. The very first notification I received was an email 2 days ago, titled "Important: Upcoming change affecting your existing domain forwarder(s)". I checked all previous communications from 123-reg and there was NOTHING received about this before December 14th.
The email did not clearly set out what the change actually was, simply stating that I need to set up a gen 2 mailbox to continue using forwarders. I'm a bit different from other users here as I never set up a catch all, instead I have several specific email addresses set up (company1@domain, company2@domain, personalmail@domain etc), forwarding to my mail mailbox. There is also no deadline date mentioned in the email.
I immediately went to check my forwarders and discovered that 123-reg have removed the interface to manage "gen 1" forwarders from their website. Far WORSE, since at least mid October, WITHOUT ANY WARNING, some of my email forwarders have been silently dropped by 123-reg whilst others continued to work. The ones dropped got less traffic which is why I didn't notice, plus the fact that my main address does still work for now.
This is a an absolute shambles. They've offered me a 1 year free subscription to their gen 2 mailbox, but I'm instead looking to switch ASAP to another domain registrar.