All skins released since December 2013 (when XMPlay 3.8 was released) are using the new xmpskin format, and any released before then are (or were) using the old xmpskin format. A few of the older skins had already been repackaged to use the new format but most of the skins on the XMPlay webpage were still using the old format until the recent mass repackaging mentioned in the first post.