13" Retina Batteries - 2013-2014 work with 2015 and vice-versa?

[bjf]

I'm struggling to figure out why 2013-2014 13" Retina batteries are not being sold as compatible with 2015 models and the other way around. Any ideas?

 

[aprendiz]

Maybe because they are not compatible????

 

[bjf]

Ok, got it, thanks, but why not? What specifically doesn't work? Have you tried it?