Hi,
I have done the integration to MS Dynamics using organization service (SOAP endpoints) and used quite complex features like entitycollection, entity reference etc.
As one of my customer has set the MFA for his accounts, not able to authenticate that customer using the existing code with organization service, even app password is not working and need to implement the secure application model. After reading a few of the links, I think the only way is to use the MS Dynamics Web API for this situation but replacing the complete integration code that used the org service by the web API is not feasible just for a customer (since I have many customers - online, on-premise, IFD and the code is same for them).
Please suggest how to deal with this.