Thank you for your answer Stefano, I notice that I did not provide all the neccesary data.
Right now we work with Dynamics AX 4.0 and have the MSSQL database on our own server. Therefore it's very easy for our other applications (in-house build) to access the AX data.
We are currently implementing Dynamics 365 CRM and Business Central (both online) but our other applications still need to access the data.
For CRM the replication to Azure works fine but we need something similar for BC. That doesn't have to be Azure. As long as we can query the data.
It could also mean we have to run CRM and BC on premise but we're exploring other options first.
Thanks,
Paul