I'm running Catalina 10.15.7 with iOS 14.4. Out of the thin air my mac pro 2019 is asking to update I don't know what software when connecting my iPhone to my mac. Why? What software?
Mac Pro, macOS 10.15
You need to update the software that allows your iPhone to communicate to your Mac.
Supplemental communication software.
Possibly to iOS 14.4.1?
Ref: Apple security updates - Apple Support
EDIT: The support article that you arrived here from should have addressed your question.
Do you know what software it is?
Software update by connecting iPhone to my mac.
