Component element and modifier delimiters don't match Drupal 8’s convention

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-5.4 version of Zen, however, uses the class naming convention that matches the one developed for Drupal 8.

If you were using Zen 7.x-5.1, you can upgrade to 7.x-5.4 and disregard the information below.

If you were using Zen7.x-5.x-dev+X, you can either stay at 7.x-5.2 or you can upgrade to Zen 7.x-5.4 using the information below.

In your stylesheets, the following selectors need to be updated:

In the comment-wrapper.tpl.php template, change the comments--title and comments--form-title classes to comments__title and comments__form-title, respectively.

In the page.tpl.php and pane-header.tpl.php templates, change the header--logo, header--logo-image, header--name-and-slogan, header--site-name, header--site-link, header--site-slogan, header--secondary-menu, and page--title classes to header__logo, header__logo-image, header__name-and-slogan, header__site-name, header__site-link, header__site-slogan, header__secondary-menu, and page__title, respectively.