The indiewebify.me h-entry validator should check to see if there are any rel="in-reply-to" or any other old rel values (see indiewebcamp wiki) or odd variants of responses, and suggest the equivalent class instead, e.g.
rel=in-reply-to/u-in-reply-to -> class=u-in-reply-to
rel=like/like-of/u-like-of -> class=u-like-of
etc.
The indiewebify.me h-entry validator should check to see if there are any rel="in-reply-to" or any other old rel values (see indiewebcamp wiki) or odd variants of responses, and suggest the equivalent class instead, e.g.
rel=in-reply-to/u-in-reply-to -> class=u-in-reply-to
rel=like/like-of/u-like-of -> class=u-like-of
etc.
Real world example: https://chat.indieweb.org/dev/2016-09-05#t1473095803155000