To use JavaDowngrader as a library in your application, check out the Usage (As a library) section. If you just want to downgrade .jar files you can check out the Usage (Standalone) section. To ...
OkHttp 5.3.2 fails with ProtocolException: Unexpected status line when client app leaks Response objects. The problem did not exist in 4.12 and may be related to this "Very small behavior change".