sequoia legacy installer package message

Hello all, I installed Sequoia 15.0 on a separate volume to test it for compatibility with my devices. To my surprise it does not allow me to install a device driver - stating 'legacy installer package', asking me to contact suppliers to help.

Is Apple really requesting that all 3rd party device suppliers have to update all their drivers to whatever the Sequoia installation package is supposed to be?

That does not seem to fit to 'increased compatibility' that I was reading in an Apple article in relation to Sequoia.

Or am I doing something wrong.

Any help or advice greatly appreciated,

Uwe