The specifications will be reviewed in May at the 2018 IIIF Conference in Washington DC, with a view to moving them to beta status. This means IIIF will enter a phase of implementation and testing to discover issues with the specifications that need to be addressed before the final releases. Additional editing for clarity will also occur during this time.
The change-logs will also be available by the 7th of May, and linked from the draft specifications.
The announcement in full is here.