2.2.5.4 release notes
2.2.5.4 Issue 2296 - Added a workaround for an issue in asynchronous Apex unit test execution that results in an internal server error when one or more test classes are specified in the request that individually contain 150 or more test methods. Now all test methods for such classes are included in the unit test run request (by omitting individual test method names). This situation is logged into the test run-level output view when it occurs. Issue 2300 - Changed the way that Apex stub classes are generated for External Services such that the Salesforce-generated stubs are used instead if possible. Note that in the absence of a first-class API for retrieval of these stubs, a potentially fragile hack is used. Hopefully it will be sufficient until a first-class API becomes available, but at present it will degrade gracefully to the original IC2-native External Service Apex stub class generation logic if necessary. I would like to know if that happens, though...