We saw most of our JS customisation break with the Catalog change that was pushed on the weekend (3rd Nov 2018). If I inspect the registration-page elements I see that you have dropped the ember.js framework. I don't see this change referenced in any of your release notes anywhere.
I also found that the 'user defined fields' behaviour has changed. We have a checkbox label that was propagated to the screen as a text string when in the past it was handled as html.
Are these intentional changes? if so were they documented anywhere?
If you are you changing your JS framework? do you have a road map for significant changes like this?