A new edition of Approved Document M, Volume 1 was published on March 1st 2016 and is available to download from gov.uk. The amendments came into force on the same date in respect of building notices given, full plans deposited or initial notices given on or after that date.
The changes are relatively minor, and are the same as the list of amendments that was sent out with hard copies to those who bought them. The changes document can be downloaded from this link on gov.uk.
One of the changes is the addition of this note to Diagram 3.8 (kitchens in M4(3) units):
"Unit length should be measured through mid-line of the worktop, not the front or rear edge."
Update: A frequently asked questions about Approved Document M document (published 21.03.16) are available to download from gov.uk