Google has removed the following structured data fields from its Google Search help documentation. Google said these were removed "since they are unused by Google Search and Rich Result Test doesn't flag warnings for them."
Here are the structured data fields that were removed:
- Under HowTo: description.
- Under QAPage: mainEntity.suggestedAnswer.author, mainEntity.dateCreated, mainEntity.suggestedAnswer.dateCreated, mainEntity.acceptedAnswer.author, mainEntity.acceptedAnswer.dateCreated, and mainEntity.author.
- Under SpecialAnnouncement: provider, audience, serviceType, address, and category.
Keep this in mind if you are using any of these fields. You don't have to remove them, it is just that Google Search and Rich Result Test won't use them.
Forum discussion at Twitter.