We've had warnings forever as users.
I have been getting messages for years about upgrading to a new version of Adobe Acrobat Pro.
I've only done it because Catalina said "NO", and I need the bloody thing once a month.
These guys are developers, I buy software for a living and I understand their pain, but seriously, siting on your arse for thirty years?
At some stage you've got to upgrade your code, launch something new if it's too much work, or just retire. Looks like they chose option 3.