The IDPF Board recently approved working group recommendations to advance the EPUB 3.1 specifications to Proposed Specification status. A public review and comment period will be open through November 7th. The final step according to IDPF policies is a member vote to approve as Recommended Specifications.
The EPUB 3.1 revision also introduces a new accessibility specification and techniques document. Both also apply to older versions of the EPUB specification. Developed as part of EPUB 3.1, the goal is to provide guidance on making conforming EPUB publications accessible.
Members and non-members can provide feedback via the IDPF GitHub issue tracker.