OSS -> Azure Health Data Fhir Service

Hi,

We currently host the OSS FHIR server in our own subscription within Azure. We are currently evaluating whether we can switch to the Azure Health Data Fhir Service but we have a few questions:

1) In our existing setup we modify some of the configuration parameters, such as the default count limit and bundle size. I can't see a way of doing this in the health fhir service, is this possible?
2) We currently use AFD in front of our fhir service. This works well but relies on the fact that we can add a custom domain to the app service so that the URLs returned in the FHIR responses match the AFD url (rather than the default app service url). I note that others have a problem with custom URLs using Application Gateway. Are there plans to allow for custom urls?
3) I note that the managed service only supports FHIR versions 3 and 4. We are not planning on using v5 anytime soon but it is concerning that support isn't available even though it was released a while back. What are the expected timeframes around new FHIR releases?

Thanks,
Reuben

[AB#118212](https://microsofthealth.visualstudio.com/f8da5110-49b1-4e9f-9022-2f58b6124ff9/_workitems/edit/118212)

Start by reviewing the three questions about configuration limits, custom URLs behind AFD or Application Gateway, and supported FHIR versions, along with linked work item AB#118212. Done would require a decided scope and documented answers or tracked product changes; no repository file or test is identified.

Written by the indexing model from the issue text.