Skylake support only really landed in 4.4 and ramped up in 4.6 to be release-ready, it's fairly well known and you can ready any release vote from 4.4 to 4.7 to

Skylake support only really landed in 4.4 and ramped up in 4.6 to be release-ready, it's fairly well known and you can ready any release vote from 4.4 to 4.7 to see commits pertaining to Skylake or the XPS13.