Apple quietly disables feature and forces macOS upgrade

I recently noticed that I can no longer collaborate on Numbers.app spreadsheets. This includes old spreadsheets that were already shared as well as collaborating on any new spreadsheets. Numbers helpfully says "It's time to update!" and sends me to the AppStore, but the new version of Numbers requires macOS 10.15 and I cannot upgrade past Mojave (10.14) as I need to keep running some old 32-bit applications.

I don't think it's reasonable to require an OS upgrade to continue using an application feature that was working fine before and I think it's completely unacceptable do so with NO WARNING at all. It's not like I'm even running some super old software, Mojave was released just two years ago and Apple is already disabling features and forcing upgrades?!

No wonder businesses are reluctant to use Apple office software. Not impressed...

/rant over