ACER have just issued the 5th version of the Questions and Answers document on REMIT, which can be found here.

There is no indication of what has changed since the last version in the document (see analysis of that document here). Closer examination reveals that following has changed this time:

• Some new answers about the process of becoming an RRM, on page 21 sections III.2.9 to III.2.12.
• A new question/answer about finding out more information on registration, which simply refers the reader to their own National Regulatory Authority. This is section III.8.3 on page 26.

Therefore unless you are registering as an RRM there is not much new information in the document.