Google has clarified in its search developer documents that JSON-LD, Microdata and RDFa are all fully supported forms for structured data and Google Search. Google wrote, "all three supported formats ...

Ever wondered how you can streamline the process of converting unstructured text and images into structured data? If you’re tired of spending countless hours on manual data entry, you’re not alone.

Google has updated the JSON files with the list of IP addresses Googlebot. I believe Google added one new IP6 and one new IP4 IP address to the list. That is, if I am looking at the file correctly.