The target release date for WordPress 4.7 is December 6, 2016. If upgrades are being put into place as they should, the platform will no longer handle image ALT attribute values the same way.
As you probably know, even though it is the best practice, websites may not always have an alt tag on images. In the past, WordPress would try to help by creating a “fallback value” for the ALT tag. It would do this by using captions or the image title. This behavior will be deprecated in 4.7.
So what does this mean?
First, this won’t impact your existing content. Existing ALT attributes will remain intact.
Second, we will all have to be more thoughtful in providing meaningful text for accessibility purposes. That is one of the key purposes of ALT Text after all. Running a periodic audit like we do for customers can help in this regard.
Third, it will mean – over time – that you can better audit ALT tags and see more quickly where none are specified. This “fallback” behavior was trying to be helpful, but unless you are using a human friendly caption or image name, the behavior creates useless ALT tags that don’t help users as many people may not rename images before upload.
If we quickly audited a website for images without ALT tags, it was possible to pass the test because ALT was present, while simultaneously being meaningless.