Phone is with Sprint: HTC Arrive
The update was not coming so I used the Force method posted on this forum.
Took some time to get it to work, though: On a Dell Latitude 4250 using verizon 4g mifi. I had to throw the wifi hardware switch on the laptop a split second after clicking update a second time. I think this is because the hardware switch is just a shortcut to the software switch. I say this because whenever I use the switch windows does not notify the connection is lost until about three seconds later. I also did the "change" on PRL and Profile, before the update (as suggested by another Arrive model user), though profile gave me an error message. Not sure doing this did anything - instead it seems just turning off the wifi switch much earlier did the trick.
One scary moment: Because I got a new 2nd computer (used for the update) Zune updater warned me i was connected as a "Guest" as this is "not my primary computer". It warned that I might lose data like photos, etc but it worked fine with no loss
After the update, several reboots, I was concerned that Zune showed 7.1 but in the phone it shows Windows Phone is 7.5 under Settings | About.
Now off to find out why all my tiles are red and learn the new features!