JDK1.1.5 caused issues with MRJ 2.1 EA1 which is an early access version of the Mac OS Runtime for Java (MRJ) that allows Java applications and applets to run on Mac systems using PowerPC processors and Mac OS 8.1. This document provides release notes and instructions for installing MRJ 2.1 EA1, which aims to address compatibility issues with JDK1.1.5 and improve support for features like Swing graphics. It also lists some known bugs and memory leak issues that were reported.