I just finished upgrading the solution to support Sitecore 9.1. It is available on github on the Sitecore 9.1 branch.
The process of upgrading was straight forward but tedious. Here are some highlights:
Installed Sitecore 9.1 to a new instance called sf91.dev.local. Added bindings and host file entry for starterkit91.dev.local and airspace91.dev.local. Updated config items in solution to point to new locations properly.
All projects needed to be updated to target .Net 4.7.2. (Right click each project, set target framework on Application tab). This ended up adding Web.config to all of the projects that didn’t have them, so instead of deleting them, I set the build action to “None”.
Biggest Hassle was redoing all the Sitecore References. Sitecore has moved to a separate nuget feed for each version of Sitecore. The Sitecore 9.1 feed is here but you’ll need to add your package source as this. Since the No Reference packages are no longer supported, this meant I had to go to each project and manuall uninstall the no reference packages and then install the updated package, choosing the option to not pull in dependencies. In the process, I tracked the Sitecore and module dependencies for each project and added it to the wiki on github here.
I used the Visual Studio Solution nuget configuration to update the versions of ASP.Net MVC and related packages. Interestingly, the version of ASP.Net MVC was 5.2.4, and all the others were 5.2.6.
I removed the DEF projects from the solution. I’ve been meaning to split that into a separate repository anyway, so I removed it completely. I’ll spend some time on that later, but for now, the core Sitecore foundation no longer depends on having DEF installed.
You can checkout the branch here. Now that the upgrade is done, I’m locally to reorganize things and also want to try to create nuget packages for modules to make it easier to work with. More on that to come.