public APIVersion APIVersion {get; set;}

'Declaration
 
Public Property APIVersion As APIVersion

Property Value

Note that FreshBooks Classic API are deprecated. It's recommended to use new Alpha API.

Different API versions require different sets of connection parameters. For Classic API you should set Server and AuthenticationToken.

For Alpha API you should set AccessToken, ClientId, CompanyNameClientSecret, RefreshToken, and OAuthStorage. The latter parameter is not required, however, without it, you will need to perform authentication every time you start the application and retrieve a new RefreshToken.

Reference

FreshBooksConnectionStringBuilder Class
FreshBooksConnectionStringBuilder Members