Confused about what type of testing - Sanity, Smoke, or Regresion

Our site runs on Dynamics 365. MS is releasing a Dynamics 365 Major Update in April. Only those currently using the Integrated version will benefit from new features and functionalities. We are NOT yet on the new integrated version. We will be performing high-level verifications to ensure that major functionalities and integrations are not adversely affected. Is this a Smoke test, a Sanity test or a basic Regression test? I am leaning towards Regression, since Sanity and Smoke are more build related-but am not sure. Your thoughts?