Version numbers are used to differentiate releases of the service. The version number is included in the WSDL URI in the format vnn, where nn represents the version number. The following is an example of a portion of a WSDL URI for version 8.
Typically, a new version of the web services description language (WSDL) document is created only when the web service introduces a breaking change. Examples of the types of changes that would necessitate a new WSDL version include the following:
Changes to the signature of an API element
Removal of an API element
Changes to a value set
The version is typically not incremented for cases where the web service adds new service operations if adding those operations will not break existing applications.
Typically, the version numbers of all web services are kept in sync; however, it is not a guarantee.
When a new WSDL version is released, the previous WSDL version remains supported for at least 120 days. This gives you time to upgrade your code to the new version. When the support period ends, calls using the old WSDL will fail. The Bing Ads API Developer blog will be used to communicate dates for removing a web service version.
The version numbers apply only to the API WSDLs and do not correspond to the Bing Ads web application. This is by design.