Since I recently went through those updates I can tell you what I did..
For the 920.. Developer unlocked the phone (bing/google it) > downloaded the preview for developers app > had to go through two updates to get the phone on denim > downloaded the windows insider app > selected release preview ring > think that I had one more mandatory update (configuration update I think) > then ultimately was able to download 10856.107 > spend a few hours and later .218 was downloaded and installed..
The upgrade path for my 635 was the same with just one hiccup. After getting on Denim I was unable to download the updates for w10 itself. Kept getting a 800.. sth error, so I removed the SD card, hard reset the phone and after I was back in (plus cancelling all downloads in the store), the phone started downloading the update and voila
Not sure if this helps you, but decided to share anyways
04-17-2016 02:47 AM