There are two parts, the Cosmos browser, and how we load the materials. The latest daily fixed some issues with how we were loading materials, that previously looked too glossy. This is why you need the latest Corona daily to have materials look correct - please note that these are not the "latest" materials in Cosmos, they are just some that did not translate well to the Corona Physical Material before, but do now after we changed how we load them. Some are materials that have been visible and available in V-Ray for some time, but were not visible and available in Corona because they did not load well.
The browser updates can do various things, always best to say yes to any of its updates :)