Ok, so there was originally no intention to release another version of Byteman running on JDK 5. However, a bug was found in the waiter code when running on Apple's JVM (look at BYTEMAN-43 in JIRA for details) and this was stopping us using Byteman internally to test the JBoss Microcontainer project.
So, I have backported the fix for this and a few other bugs and released Byteman 1.0.3.CP01. The source and, binary zips and release notes are available from the releases page:
The latest 1.1.0 release, which includes the capability to dynamically upload rules ot a running program, is available from the main downloads page:
The next 1.1.1 bugfix release is in preparation.