Well, I am now on Threshold. It says version 1511, build 10586.14. The bad part is that I had to do a completely clean install and lost everything. What happened was that I read somewhere that all SATA controllers should be set to IDE in the BIOS. I changed mine and tried to upgrade from a disk. It failed again, and now the computer would not boot into Windows at all. Checking with the repair tools said I no longer had any installation of Windows. Booting from a disk and trying a reset wouldn't even work. After trying everything to restore boot, I finally used the MiniTool Partition Wizard on a CD to delete all partitions on the drive thus wiping out everything. I then used a disk I had created from the 10586 disk ISO I had previously downloaded with the Media Creation Tool (before they pulled it). I booted from the disk and installed Windows 10 with no problems. I recovered all of my personal files from the AOMEI backup I had done on the second HDD but now I'm in the long process of installing all of my programs again. I have most of the regular stuff reinstalled. Now I have to do the games. I have to reinstall Steam, Origin, Uplay, and GOG Galaxy and redownload the games I want to continue playing. I was able to copy over World of Warcraft in it's entirety from the backup file and it works fine. There may be a way to copy Steam and LOTRO over but I'll have to check. I know I did it with one or both of those before.
Threshold is working very well but really doesn't seem any better than 10240 was. It has already received a few updates.