I don't know an official answer, but historically, any new functionality introduced in AGOL is typically released in ArcGIS Enterprise in the Enterprise version following the release in AGOL.
Technically, 12.0 was released right after that functionality was released in AGOL in October of last year. But, that might have been too soon for it to make it to ArcGIS Enterprise, so I would guess it will be released in 12.1 later this year.
