We've been using ProGuard 4.0 and 4.1 happily to obfuscate our MIDlet for some time now. Recently I tried out ProGuard 4.3 and 4.4 and found that it fails somewhere along the line:
{{{
-eclipseme-obfuscate:
[wtkobfuscate] **************************************************************
[wtkobfuscate] * Antenna 1.0.1 initialized for project "MIDlet" *
[wtkobfuscate] * Using Sun...