https://www.cyanogenmod.org/blog/a-fork-in-the-road So finally has happened what had been feared for some time. Let's hope that Lineage will find its way. I've been a long-time CM user. The CyanogenMod forum "is currently unavailable".
I'm optimistic that we will see LineageOS updates soon. Btw, here's their homepage. FWIW, nightlies can still be downloaded from https://download.cyanogenmod.org/. The 20161225 nightly for my S5 finally fixed the rotation problem.