Artist’s description from DA:

I couldn’t help but notice that in last week’s episode, the stallion pegasi standing at this angle had a couple of subtle changes to their design, or basically some kind of revamp, at least, from what I saw.  Namely, this wing, which looks different than before, and the little joint from where the rump goes to the hindleg actually looks like two separate strokes, rather than just one stroke.  I think we even saw part of a new stallion-specific walk cycle for stallions at this angle, too (of course, it’s probably more likely that it’s something I’ve never noticed before, in which my hunch was correct as it’s been around since the Crystal Ponies’ debut at the beginning of Season 3, where the Crystal stallions had stallion-specific revamps to their design, as opposed to upscaling/recycling mare assets, but not applied to the usual background ponies until here).  

I don’t expect anyone (unless you’re also a vector artist or also pay too much attention to pony design for your own health like myself, maybe) to understand what I just wrote.

Anyway, not sure if I like this new wing design.  All I did compared to the original screenshot was rotate the head clockwise a bit.