Breaking changes:

• GNU Emacs 27.1 or later is required.
• Don't allow space between label and text in reference link same as CommonMark GH-774
• Whitespace is required before the closing sequence of an atx header. GH-778

New Features:

• Introduce markdown-fontify-whole-heading-line variable for highlighting
  whole header line. GH-705 GH-773
• Backslashes in escape sequences are now treated as markup. GH-377

Improvements:

• markdown passes buffer-file-name as a parameter to
  markdown-command when markdown-command-needs-filename is
  t and markdown-command is a function.
• Support newer version Eldoc ships with Emacs 28.
• Don't spell-check against pandoc references. GH-572
• Support tree-sitter-based major modes used by Emacs 29.
• Highlight "geo" URI scheme GH-739
• clear-image-cache to make toggle inline image update.
• Highlight autolinks if a scheme is valid and it is not registered in markdown-uri-types
  GH-743
• Improve horizontal rule rendering in markdown-view-mode GH-753
• Don't load major-mode if it isn't in auto-mode-alistGH-761
• Improve markdown-insert-table prompt message GH-771
• Consider major-mode-remap-alist to determine major-mode for code blocks GH-787
• Set marker after footnote reference GH-793
• Improve putting text attribute for indented blocks GH-794

Bug fixes:

• Don't override table faces by link faces GH-716
• Fix invalid italic fontification after bold markupsGH-731
• Fix markdown-live-preview-mode fails when eww-auto-rename-buffer is non-nilGH-737
• Fix to mistake to handle the line as delimiter rowGH-747
• Fix wrong displaying horizontal rule in markdown-view-mode GH-747
• HTML-escape title in markdown-add-xhtml-header-and-footer markdown-xwidget-issue-9
• Fix wrong inline link parsing that has link titleGH-762
• Don't treat backslashes as escapes inside literal blocksGH-766 GH-768
• Fix markdown-enter-key doesn't delete empty checkbox listGH-786