We're hosting multiple DNN sites (500 +). Here's our setup:
1. One "Master" application code
2. Created links (junctions) on windows server for the rest of the sites so that they all share the same code base
3. Each site has it's own dnn database and web.config pointing to it's database

We're trying to upgrade to 5.6.1. I've upgraded the "Master" code and "Master" database. Is there a way I can upgrade the rest of the databases since they all share the same code? I am trying to see if I can run some script to upgrade all these databases w/o having to break the link and upgrade each site individually. We have some unique situations and could not use child portals (different customers having same user ids etc..)

Thanks for the help!

About the only way you could make something like this work - would be to build a custom upgrade module based around the Upgrade.vb code in 
DotNetNuke.Library - Services.Upgrade.Upgrade.UpgradeApplication()

The reason for this is that the jump from 4x to 5.x includes more that just sql scripts to update data structure - there are changes needed in layout of tabs in the Admin / Host area for example - that are handled by the Upgrade module using program code.

The upgrade process uses scripts in the \Providers\DataProviders\SqlDataProvider folder to update the structure of the database - and then runs a whole heap of core api code routines to handle all the more complicated transition steps.

You would need to duplicate all of these processes -  AND you would then need to replicate the same process for EACH module in use on your site - although in this case as a rule for modules you are looking at just running the sql scripts in each modules individual SqlDataProvider folder.

WESTA 

Oh and you would also need to do the same for providers and skin objects - or anything else that needs updating.

Westa