I assume this is referring to passing hashes in as parameters to methods. Ruby 3 made this more explicit; you must use ** to convert a hash into positional arguments and you must use {} around your key/values if the first argument is a hash.
I'm glad the light was eventually seen after 25 years, but that's a significantly breaking change which means the update often doesn't happen. A lot of Ruby 2 codebases still exist with people still doing Ruby 2 bad behaviors.
It was a breaking change, but it was really small and affected only very few usages. Most places just went on with no changes. It was not at all a painful change.
Also Rubyists as a whole tend to update to the newest Ruby fairly fast. There are of course places that don't upgrade quickly (especially legacy systems that are barely touched), but most places with living code bases seems to be very quick when it comes to updating nowadays.
I assume this is referring to passing hashes in as parameters to methods. Ruby 3 made this more explicit; you must use ** to convert a hash into positional arguments and you must use {} around your key/values if the first argument is a hash.