Redmine

This removal is correct for core, but many third-party plugins still use raster icons. As a result, their icons no longer render correctly since r24029.

Plugins probably use raster icons for various reasons. One is that they need to remain compatible with Redmine 5.1 and earlier. Another is that the author has not yet found the time to migrate to SVG icons.

To preserve compatibility with existing plugins, could you consider reverting r24029?

Before r24029 (redmine_issue_templates plugin):

After:

Before r24029 (Administration page with two plugins installed):

After:

Marius BĂLTEANU wrote in #note-6:

I prefer to not keep this complexity in the core just because we break some plugins, but I'm open to provide a easier way for plugins to keep the compatibility. Maybe one option is to move all the rules to an icons-legacy.css file and let the plugins include the file based on their needs? Any other suggestion is welcomed.

The attached patch adds legacy-icons-compat.css that provides styles for legacy icons. A plugin developer or user can restore the appearance of legacy icons just by importing legacy-icons-compat.css in the plugins stylesheet:

@import url('/legacy-icons-compat.css');

Thanks for taking care of this, I've committed the patch. I still recommend to invest the effort in moving the icons to the new svg icons.