The PNG Working Group
has published a First Public Working Draft of the
Portable Network Graphics (PNG)
Specification (Third Edition).
Completely backwards compatible with the millions of PNG graphics conforming to
the older (2003) Second Edition, this new edition folds in reported errata and clarifications
and also adds some much-requested new features:

• Animated PNG, widely implemented for a decade but not part of the
  official specification until now
• Coding-Independent Code Points, which clearly identify the color space
  used by a graphic for improved rendering fidelity without blowing up the file size.
  This includes support for High Dynamic Range (HDR)
  color spaces such as BT.2100 HLG and PQ
• Support for EXIF metadata

The PNG Working Group will continue to refine the PNG specification, including
handling newly reported bugs,
tracking implementations, and
adding Web Platform Tests for the format.

Original source: https://www.w3.org/blog/news/archives/9718