Techniques for masking version differences among multiple applications providing similar services over a network include receiving, at an application-switching component, from a requesting process, a request for a service among the similar services. The request includes data indicating a particular service extension is mandatory. The request is sent to a first application. In response to sending the request to the first application, error data is received. The error data indicates the particular service extension is not available at the first application. In response to receiving the error data, the request is sent by the application-switching component to a different application of the multiple applications. These techniques allow a provider of multiple servers to prevent a Simple Object Access Protocol (SOAP) mustUnderstand error, indicating a lack of a mandatory extension, from being sent to a client when at least one of the servers includes the extension.