Like most of you, I'd forgotten that the One (E8) even existed before today. In case you need a quick refresher, the One (E8) is pretty much a plastic-bodied, 16GB One (M8) that traded the M8's 4MP rear camera for a 13MP unit. It debuted on Sprint around two years ago, sporting the then-current Android 4.4.2 KitKat. Now, it's upgradable to 6.0 Marshmallow.
Over the years, the Sprint One (E8) received just three updates; one that added Wi-Fi calling, one that added 5.0 Lollipop, and one that patched Stagefright (yeah, remember that?). That last one occurred a year ago, so it's surprising to say the least that Sprint is updating the E8 to 6.0 at all. For reference, Sprint upgraded the M8 to Marshmallow back in January.
The E8 is being upgraded to version 3.10.651.6 from 2.32.651.11. Sprint doesn't include a very long changelog, only saying that the update "will include all current security patch updates". If that's true and the E8 is indeed packing the August patch, HTC and Sprint deserve some praise.
If you have a One (E8) on Sprint, let us know which security patch the update includes. The OTA began rolling out earlier today, and all Sprint E8s will have received it by August 29th.