Bug fix for the skip-link component missing the "visually-hidden" class.
If you have overridden the html.tpl.php, page.tpl.php, or zen-main.tpl.php templates, add the visually-hidden class next to any HTML element that has a visually-hidden--focusable.
If you have an existing Zen 7.x-6.x sub-theme, you should copy the changes in _button.scss to your sub-theme; the only change was dividing the existing properties into a few new ruleset selectors.
If you've built a sub-theme with Zen 7.x-6.0, you don't have to udpate any files, but if you need RTL styles, you will need to delete your node_modules folder and re-run npm install to get an upstream fix to Zen Grids.
After the release of 7.x-5.1, the -dev version used a class naming convention that ended up not matching the Drupal 8 class naming convention that was developed later.
Since many, many developers used the -dev version on production sites, the 7.x-5.2 release of Zen uses the same class naming convention that existed in the -dev version. This makes updating from the -dev version to 7.x-5.2 easy.
The 7.x-5.3 version of Zen, however, uses the class naming convention that matches the one developed for Drupal 8.
After the release of 7.x-5.1, the -dev version used a class naming convention that ended up not matching the Drupal 8 class naming convention that was developed later.
Since many, many developers used the -dev version on production sites, the 7.x-5.2 release of Zen uses the same class naming convention that existed in the -dev version. This makes updating from the -dev version to 7.x-5.2 easy.
The 7.x-5.3 version of Zen, however, uses the class naming convention that matches the one developed for Drupal 8.
Please read the instructions at https://drupal.org/node/1588228 for information on how to upgrade your Zen sub-theme to this version or to 7.x-5.3.
