We’re working on adding support for the _history endpoint. This should be ready in about a week.
I’m crying out for this myself as it would help with issues I’m having with Azure FHIR servers right now. Hence the priority. 
And we’re working on handling _include and _revInclude parameters. This is a much larger piece of work and will take some time. The devil is in the user interface here - building screens that can render included resources in a user friendly way is not easy.
And we’ll be fixing bugs!