4.36.10.2864 replaced 4.36.10.2700 because it had some significant issues.
When that occurred, 4.36.10.2700 was pulled from OTA and Flash update availability. Anyone who had not yet updated to 4.36.10.2700 when that happened could go from 4.36.9.139 to 4.36.10.2864. But, when that version was halted, those who were still not updated to a 4.36.10.xxxx variety were stranded at 4.36.9.139.
4.36.10.3406 was the fix for those on 4.36.10.2700 or 4.36.10.2864 and is still available by OTA for anyone with a 4.36.10.xxxx cam.
Given how the 4.36.10.xxxx firmware has been performing since its first appearance, I would say that it is out of an abundance of caution that they are still evaluating how 4.36.10.3406 is running before a mass release to millions of cams.
