The Dell OptiPlex 3040 Micro also runs Skylake with no upgrade path

Like its 7040 sibling, the 3040 Micro runs 6th Gen Skylake on LGA 1151 — including the i3-6100T, i5-6500T, i7-6700T, plus Celeron and Pentium variants. Same socket, same generation lock, no Kaby Lake compatibility.