Google has supposedly sent out emails announcing upcoming changes to the AdSense platform in the upcoming weeks. I have not personally received such an email but there are some in the WebmasterWorld forums that received it. It covers changes to the "Your Ads tab."
Here is the email:
We're committed to continuously investing in the modernization of our advertising products. As a result, there are some important changes we're making to some AdSense features that you have used or configured in the past. Your Ads tab will be updated in the coming weeks to reflect the following changes:Ad types
We’re moving towards richer ad formats, phasing out text-only and display-only ad units to further improve user experience, and to fully reflect the pool of ads we have in the market. As a result, the "Text ads only" and "Display ads only" ad units in your account have been renamed to “Display ads” and from early 2019 will be updated to serve all ad types.
Text ad styles
We’re deprecating text ad styles for "Text & display ads" ad units. From now on, you won’t be able to create ad styles for your new ad units. Your new ad units will have Google-optimized text ad styling. As this feature is being deprecated, your existing ad styles will also be optimized by Google in the following months. For customization and improved user experience, you can use native ads on your site.
Simplifying “If no ads available”
We’re continuously working to increase the quality and safety of our ad network and reduce the number of malicious ads that enter the AdSense network. As a result, we're removing the “If no ads available” option and we’ll be defaulting to collapsing the ad space or showing a blank space instead. If your current setting is a color or another URL, it will be updated in the near future your current settings will stop serving in the near future.
So keep these in mind - I am surprised I didn't get this email yet.
Forum discussion at WebmasterWorld.