I'm building a program to post new SD requests to Microsoft Teams, but trying to read documentation and other peoples work I'm getting so confused. 

The URL for my API is /sdpapi/ - in other topics on this forum i see people using /sdpapi2/ and /sdpapi3/ URL's.

The documentation I'm currently using is instructing me to use /sdpapi/ - but in the same document there is information about migrating from API v2 to API v3 (but nothing about migrating from V1?)

Can somebody help me clarify on the state of the API? Should i upgrade?

Is some of the output JSON based and some XML based?

My current SD plus version is 9.3 build 9317. 

Thanks in advance

Arve A