The 50mb cellular limit is still there. 'Automatic App Updates' is now a toggle in the 'Use Cellular' setting. I assume if you chose to use cellular, only those apps which are under 50mb will be updated automatically.
I personally don't allow this and so far it's been working great. I do like that I get a notification telling me which apps have been updated, clicking this opens the App Store to a list of recently updated apps sorted by day. You can then look at the changes for each app.
I'm glad we can do this as checking for app updates (and reading the change log) has been part of my morning ritual for years now.