The 1.7.10 version of this mod backports the added skin layer and the asymmetrical limbs of the 1.8+ skin format, but it has the following shortcomings:

• transparency isn't supported (even though it is on Ears parts). This can be partially fixed by using Et Futurum's enableTransparentAmour option, but it doesn't fix the first person arm.
• slim skins aren't supported
• the skin overlay is thicker than it is in newer versions (tested on 1.17.1)

Et Futurum's skin backport has neither of these issues, but it can't be used together with Ears. It would be nice if there was a way to get the best of both worlds. Either by implementing the missing functionality within Ears, or by changing the patching to be less aggressive so it can coexist with EF's skin renderer. EF's skin renderer has poor mod compatiblity since it works by replacing vanilla classes, so the former option would be preferable.