macos – what generates this message to update?

so im on os catalina 10.15.7 and ios 14.1. This am when i connected my iphone to mac, i got this pop up. Its 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. What is it for ? Whats it mean? Anyone else get one?

connection message