API Version for Dynamics CRM Online and On Premise app

Hi Dynamics CRM team,

We are developing an integration for which i was doing data analysis. I had a query regarding  the API version for MS Dynamic CRM REST APIS

What all APIs versions are released for Dynamic CRM?

May I know the release dates. What is the frequency of these API releases.

This data I need to conclude on which API version should we support for connector development.

I could see v8.1 used in some methods example

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GET [Organization URI]/api/data/v8.1/accounts?$select=name&$filter=contains(name,'sample')&$count=true HTTP/1.1 Accept: application/json OData-MaxVersion: 4.0 OData-Version: 4.0 Prefer: odata.maxpagesize=3

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I could also see version 8.0 used in few documents. Could you please let us know which is the stable and released API version used for MS Dynamic CRM 

Awaiting response

Thanks,

Rajinder Singh