Programs and libraries compressed by UPX are completely self-contained and run exactly as before, with no runtime or memory penalty for most of the supported formats. UPX supports a number of different executable formats, including Windows programs and DLLs, macOS apps and Linux executables.

* bug fixes - see https://github.com/upx/upx/milestone/1 Changes in 3.91 (30 Sep 2013): * Added experimental support for Windows 64-bit PE files, based on work by Stefan Widmann. Please use for testing only!