We are undertaking a project to migrate our existing DNN 3.x site to DNN 4.5 (and .NET 2.0).  I am currently musing between two paths to take.  First, create a migration version of the site and apply the DNN 4.5 upgrade or second, create a fresh install of DNN 4.5 and being migrating our 3.x modules into the new site.  I can see problems with either.

If the first, it beleive it will be necessary to freeze the 3.x site from change until the migration is complete.  Having the site frozen for a possble long time could be problematic.  With he second, I wonder about migrating the 3.x database to the 4.5 site (users, passwords etc.)

Just wondering how other may have handled the migration and which path was taken.

I have done the same and upgraded a version 3.3.7 site to version 4.5.3 without difficulty reccently. There are a number of ways this can be accomplished with minimal downtime and possibly not having to freeze the site (or just hang out an "offline for maintenance" html page for a few hours). Of course before accomplishing any kind of upgrade you need to back up the original installation files and database and ensure ASP.NET 2.0 is running on your sites. All of the users, passwords, etc wil not be affected after the upgrade.

First, you can jump right in and using the upgrade installation go for the upgrade knowing that if anything occurs you can reload the original site with your backups.

Another method and one I have used before is to create a replica installation on my local machine with copies of the backup files and database. You can then apply the upgrade without worry about messing anything up and if it goes well you have a complete running upgrade of your site (remember to add your localhost installation to the portalalias table first) or if not you can readjust your procedure and start again. At this time you can attempt to upgrade your original site or reload the installation with the functiong upgrade from your local system.

If your site is real large and ftping the files back and forth creates a time constraint you can practice with a new installation of the starting version and applying the upgrade just to give yourself an idea of how it will progress.

I have also tried the process of starting with a clean install and rebuilding the site from the old one. If the site is very large at all it becomes a huge time-consuming project and one I don't plan to undertake again.

Good luck,

Mike