When will Essentials Role/SKU be added to 2019 Insider Preview flights?

Is there any expected timeline for when the Essentials Role (and Essentials SKU) will be included in the Windows Server 2019 Insider Preview flights? Very keen to start to understand what has been changed, fixed and/or improved in this aspect of the server platform - and to make sure that some fixes needed to Essentials have come through in 2019.