determine if we are using Rest API with the latest version of authorize.net V1.9.5 SDK

[pravalli555]

1. How could we determine if we are using Rest API with the latest version of authorize.net V1.9.5 SDK?  Is there any settings we need to configure or is it pre-built inside the framework.
2. What version of authorize.net SDK did the SOAP got deprecated?  
3. Is there a release notes available for all the SDK versions.