How do I know which API version I am currently using (REST APIs)?

Only the base URL is sufficient.

• New APIs (v2) → URLs starting with:
  • https://mis.kotakneo.com
  • https://cis.kotakneo.com
• Old APIs (v1) → Any legacy URLs outside the above domains

If your REST calls start with mis.kotakneo.com or cis.kotakneo.com, you are already on the new API stack.