Google has added a new alert to Google Search Console, this time for favicons for sites that are still utilizing the older and smaller favicons for their site.
Paul Macnamara shared the screenshot of the new alert.
For sites with favicons that are lower resolution, Google is sending this alert out asking site owners to update their favicon to a 192x192px high resolution favicon. Google specifically references Chrome new tab pages and Android home screen, so especially if you have a site that someone might add to their home screen, updating this icon should be a priority.
Many sites still have legacy favicons, which started 16×16 and later 32×32 in size. And it is very easy to be able to create a nice favicon with the updated size Google wants.