UPX v3.04w is released. UPX is a free, portable, extendable, high-performance executable packer for several different executable formats. It achieves an excellent compression ratio and offers very fast decompression. Your executables suffer no memory overhead or other drawbacks for most of the formats supported, because of in-place decompression. UPX is copyrighted software distributed under the terms of the GNU General Public License, with special exceptions granting the free usage for commercial programs as stated in the UPX License Agreement.UPX uses the NRV compression library for compression services. A compatible but somewhat less efficient OpenSource implementation is available through the UCL compression library. UPX aims to be Commercial Quality Freeware.

UPX v3.04w Changelog:
- new format Mach/AMD64 supports 64-bit programs on Apple Macintosh.
- new formats Dylib/i386 and Dylib/ppc32 support shared libraries [such as browser plugins] on Darwin (Apple Macintosh). An existing
-init function (LC_ROUTINES command) is required.
- new format vmlinuz/armel for Debian NSLU2 (etc.) linux kernel
- bvmlinuz boot protocol 2.08 for 386 Linux kernel
- Extended ABI version 4 for armel-eabi ARM Linux ELF
- bug fixes

Download: UPX v3.04w
Source:Here