Automatically updating a stack - How Do I Do It?

[Len Morgan]

As I'm getting my app finished up, I've come up with a question about 
how exactly to update a stack from a server.  The software will be 
loaded on a workstation initially and stackRunner will get the process 
going.

I'd like the app to check for newer versions on my server at startup.  
I've stored a custom property in each stack that has a version and a 
build number but it occurs to me that I can't get that information until 
I "start using" the stack.  Once that's done, if I find (through a 
onPreOpenStack handler) that the server has a newer version, how can I 
download the newer version?  Will I have to notify the user that a new 
version has been downloaded and require them to restart?  Can I change a 
running stack (reload the updated version without reloading the OS 
cached version). 

Is there a better way to handle this before the stacks are ever opened 
(like encoding the version/build number into the filename of the stack?  
Should I just notify the user that there is a new version available and 
have them push a button to download it, then restart the program?  I'd 
like to notify the user that a new version is being downloaded but don't 
want to require much more from them if at all possible.

Note that my app is spread across several stacks and I want this update 
ability in all of them but not have to download the entire set of stacks 
if only one of them has changed if I can avoid it.

If there is a tutorial available that already explains this, please 
point me to it.

Thanks!!

Len Morgan