Google announced this morning that after April 6, 2020 it will no longer support the data-vocabulary markup for rich results. Google is going all in with Schema.org. Google said "with the increasing usage and popularity of schema.org we decided to focus our development on a single SD scheme."
Google is giving SEOs, webmasters, site owners, etc a few months to transition from data-vocabulary markup to schema.org markup. In fact, over the next few months, Google will be contacting those who have implemented data-vocabulary markup via Search Console with warnings. This way those who do not follow Google on the blog or other social channels will be notified.
Google wrote "As a preparation for the change and starting today, Search Console will issue warnings for pages using the data-vocabulary.org schema so that you can prepare for the sunset in time. This will allow you to easily identify pages using that markup and replace the data-vocabulary.org markup with schema.org."
There isn't a huge difference between the two markups.
Here is schema.org:
Here is the same thing in data-vocabulary:
This will impact the rich results report after April 6th. Google wrote "Starting April 6, 2020, Google will no longer support data-vocabulary.org structured data to enable rich results in Google Search. From January 20 until April 6, any data-vocabulary.org structured data on a web page will trigger a warning for the appropriate rich result type. After April 6, an error will be triggered."
Forum discussion at Twitter.