Contribute to the theme v8 -> v9 upgrade guide

Hi all,

We have begun a v8->v9 theme upgrade guide here. This includes some of the main questions and stumbling blocks we have encountered or seen folks encountering in the community. Please have a look, bookmark it for your reference as you’re working on your themes and add-ons, and most importantly, if you have any other things you think would be helpful to add go ahead and post them as a reply to this thread! Thanks!