What generates this message to update? I'm on macOS Catalina 10.15.7 and iOS 14.1.  This AM when I connected my iPhone to Mac, I got this pop up.  It is not something I see re: regular updates - never gotten it before.  I just X'd through it and continued as usual. I recently synced the other week with all the same software and didnt get it.  Have not made any os or ios updates or changes to warrant message.  I did use the Learn More linkbut did not get any useful info from Apple other than then saying its needed to connect - which is is NOT as i X'd through it and was able to connect.  What is it for?  Whats it mean?  Anyone else get one?
Not a definitive answer, but anecdotally…
It's happened on every Mac here that is linked to an iOS device, on first connect after 14.1/14.2 [we held off 14 for a while]
Why, idk, but yes, something changed [or is about to change once you do update to 14] in the phone/pad that needs a macOS/iTunes update.
No Catalina here, but his happened on both High Sierra &amp; Mojave Macs. I had assumed, prior to your question, the it was because we weren't up to date on macOS itself, but it seems not to be the case.