OxygenOS 3.2.8 (MM) OTA for OnePlus 3

[fuzzylumpkin]

Umm, what exactly does that mean?

Substratum is a theme engine along the lines of what Google should be including in Android. It doesn't mean anything bad if you don't know what it is or how to use it. To me it basically means I can't have dark notifications, which sucks. I blame Google.