datahell is right, check if files are really updated. In linux hosts, I guess that the following quote from http://linux.about.com/od/commands/l/blcmdl1_unzip.htm
, is true:
unzip will list, test, or extract files from a ZIP archive, commonly found on MS-DOS systems. The default behavior (with no options) is to extract into the current directory (and subdirectories below it) all files from the specified ZIP archive. A companion program, zip(1L), creates ZIP archives; both programs are compatible with archives created by PKWARE's PKZIP and PKUNZIP for MS-DOS, but in many cases the program options or default behaviors differ.