As mentioned in the article, 30% of our customers have been switched to the new JMAP-based interface. We’ll resume migrating the rest in the new year.

For clarity, we’ve only had beta users (other than ourselves) on the JMAP-based interface for a few months. The previous interface (which has been in use since the start of 2012) was built on the precursor to JMAP, which works in a broadly similar fashion.