iPhone 15 Pro not connecting at USB 3.1 speeds on USB-C port - Solved by updating to IOS 17.3

This isn't really a question. I just want to share my experience with the USB-C port on my iPhone 15 Pro Max.

Yesterday (4 Feb, 2024) I was trying to transfer 200 GB of Prores video files from my iPhone to my Macbook Pro and I was finding the transfer was only going at about 40 MB/sec. Looking at the System Report on my Mac I could see my iPhone was only connected at USB 2 speeds -- "up to 480 Mbps" -- and not at USB 3.1 speeds. Even though I was using a Thunderbolt 3/USB 3.1 cable that worked fine connecting to a 10 GbE network adapter. In fact, I tried 3 different cables all with the same spec and similar results.

At the time, my phone was running iOS 17.2.1 and Apple Support suggested I should update to iOS 17.3 "to see if the problem went away". Indeed, after updating the phone is now connecting to my Mac at USB 3.1 speeds "up to 10 Gbps". And transfers are running at about 250 MB/sec (about 6x faster than before). Same cables.

Hopefully this information will help someone else!