WireMock

4.0.0-beta.22

has just been released with some notable changes around how data classes are transformed and mutated. By default, data classes like the

StubMapping

class are now immutable, and must be transformed via their respective builder classes. This immutability update comes with some breaking changes to those data classes so we're keen to hear your feedback! More information on which classes are affected and how to use the new builder pattern can be found here