The stub which is imbedded in each UPX compressed program is part of UPX and UCL, and contains code that is under our copyright. The terms of the GNU General Public License still apply as compressing a program is a special form of linking with our stub. As a special exception we grant the free usage of UPX for all executables, including commercial programs. See below for details and restrictions.
All rights remain with the authors.
See the GNU General Public License for more details. The stub which is imbedded in each UPX compressed program is part of UPX and UCL, and contains code that is under our copyright. The terms of the GNU General Public License still apply as compressing a program is a special form of linking with our stub. This also implies that the UPX stub must be completely unmodfied, i.e. the stub imbedded in your compressed program must be byte-identical to the stub that is produced by the official unmodified UPX version. The decompressor and any other code from the stub must exclusively get used by the unmodified UPX stub for decompressing your program at program startup.