Jeremy Cherfas
Replied to a post on cdevroe.com and a post on colinwalker.blog :
Not sure whether you mean incoming webmentions or outgoing webmentions that aren't working, but for outgoing, there's no class="u-in-reply-to" on your post about Colin Walker's post.
I will take a look into this... but I do not think that is required. It should work just with a link.
Colin Devroe, Aug 07 2017 on stream.jeremycherfas.net