The themes made unavailable in December will be retired completely on the 30th of January along with themes that were removed from the theme picker in 2015.
Removal of old and unmaintained themes will allow us to update Glow Blogs and keep blogs secure.
If your blog uses on of the old themes, it will be automatically switched to the Twenty Fourteen theme on the 30th of January 2020. As this may result is a few changes to your blog appearance, menus and widgets we suggest that you change your theme before then.
You can find out more about the process on Glow Connect:
Themes being retired include: classic, default, digg3, dundee, fjords, K21.0.3, oxygen, p2, regulus, suburbia, suffusion, visual and wp-andreas01.