In what dimensions are PL and Diff equivalent? I have read in different places, that for $n\leq 4$, PL and Diff are equivalent (passing through PDIFF). I believe Milnor gave an example of the inequivalence for $n=7$. What about for $n=5$ or $n=6$? Are there examples of PL manifolds which are not smoothable?

A more qeneral question is References on the relations between Top, Diff and PL. It gives a reference to https://mathoverflow.net/q/96670 which gives a complete (positive) answer for $n =5, 6$.
