Microsoft have release Windows Phone 7.8 in the last few days. As usual the rollout appears to be phased, I think based on serial number of your phone. As with previous versions you can force the update, so jumping the phased rollout queue. The process is

  1. Put the phone in flight mode (so no data connection)
  2. Connect it to your PC running Zune, it will look to see if there is an OS update. If it finds it great, let it do the upgrade
  3. If it does not find it, select the settings menu (top right in Zune)
  4. You need to select the update menu option on the left menu
  5. Zune will check for an update, about a second or two after it starts this process disconnect the PC from the Internet. This should allow Zune to get a list of updates, but not the filter list of serial numbers. So it assume the update is for you.
  6. You should get the update available message, reconnect the internet (it needs to download the file) and continue to do the upgrade

You will probably have to repeat step 5 a few times to get the timing correct

I also had to repeat whole process 3 three for 3 different firmware and OS updates before I ended up with 7.8.

image

But now I have multi size tiles and the new lock screen.

Or if you don’t fancy all the hassle you could just wait a few days