Google says automatic ads and upcoming initiatives will fulfill the plugin’s functionality.
Google AdSense has sunsetted its WordPress plugin this month. Publishers can no longer install it on their sites. As of April 5, 2017, those currently using it will not be able to make ad format updates through the plugin.
Google said on the support page for the plugin:
After reviewing the AdSense Plugin for WordPress, we’ve decided that going forward we can better support WordPress publishers through new innovative features like our automatic ad formats and other upcoming initiatives.
Publishers currently using the plugin should look out for an email with “more information and advice,” says Google.
As of May 3, 2017, there will no longer be support or access to the plugin.