The 8th Edition has some genuine, ground breaking changes* compared to the previous editions, and we're now in the process of reading through the manual to work on creating a new MLA style LibGuide.
The current guide will be updated over the next few weeks (keep an eye out for when we switch from saying "7th edition" to "8th edition"), and a new guide should come out next year (unless we finish it earlier).
If you are an EndNote user, it's important to note that the style marked simply "MLA" in EndNote is the old version, but there is a new "MLA 8th" style available in the latest version of EndNote.
If you don't have "MLA 8th" available in your list of styles (when you hit "select another style"), then you will need to go to the Help menu in EndNote and click on "check for updates".
The new style is currently a beta version, so there may be some bugs in it. We recommend that you run EndNote updates regularly (say, at least once a semester), so you can get any new features that have come out.
*No, seriously, this is quite remarkable. They've actually changed the internal logic behind the style, and it's flowing out in all sorts of directions. Librarians all over the world are geeking out.