[Zope] sending updates with zope.

hi to all, i have this problem which is related to zope. we sell a tool inside zope that we install on a machine that stay at our customer. We need to find a easy but powerful way to update the tool if there are bugs or new features . after some research i've found zope synchronizer which is quite good but it miss some function (i.e. checking the file instead of just checking mtime ) and i would like if there are other products or solutions Any hint is well appreciated. thanks Samuele