Is there a fix for the future version of MacOS for those systems with software that will be incompatible with it?

The legacy extension popup in only to get users to contact developers and encourage them to modify their software to avoid requiring kernel extensions. Most developers already have done that if they support Big Sur.

DO NOT attempt to remove any such extensions from OS 10.15. It still needs any that are there,

I am a newbie but i did find this support page specific to legacy extensions and MacOs.

See support apple com /en-us/HT21099

Seems extensions need to be updated by developers from 32-bit to 64-bit. And maybe security and privacy? Some developers haven’t yet or will not. At this point, we may need to ask devs if they plan to comply in Catalina or even Big Sur.

Your Mac is qualified to run 10.15 Catalina. But without an SSD upgrade, it is likely to be a little slow.

Apple says it can't go any farther, likely because its intel graphics can't draw stuff fast enough for an appropriately-responsive user experience.

There are about 130 computers form 2006 to present day that bear the name MacBook Pro.

What MacBook Pro are we talking about, by year, early mid late, screen size and processor speed.

I have a 13 inch, Mid 2012 2.5 GHz Dual core Intel i5

Yes it is running the MacOS Catalina 10.15.7 but a Legacy pop up alert still came up so I was wondering if I needed to do anything else.

Thanks for the info!

Thankszz