@JeremyECrawford The Blood Hunter is listed as an additional class on D&D Beyond, under official classes, was it made official?

— Keith (@Glytched) January 30, 2018

The only official classes in D&D are in the Player's Handbook. For a new class to become official in the future, it must appear in a D&D book or must be announced as official by the D&D team. #DnD @DnDBeyond @Wizards_DnD https://t.co/2iRz4feoNV

— Jeremy Crawford (@JeremyECrawford) January 30, 2018

The Blood Hunter is actually categorized under 'Additional Classes' everywhere it appears in DDB. It is specifically not under 'Official Classes' and is not considered official.

— D&D Beyond (@DnDBeyond) January 30, 2018

This. 🙂

— Matthew Mercer (@matthewmercer) January 31, 2018

You can download Blood Hunter class here:
http://www.dmsguild.com/Blood-Hunter-Class