Migrating SharePoint 2013 apps to 2016

Question

I have about 12 SharePoint apps (or add-ins) that I need to migrate over to 2016, but whenever following the steps below, I'm not seeing the app webs, nor the ability to add any apps to an existing page.

1. Create App catalog
2. Upload/Install all 2013 apps
3. Backup ContentDB, App Management and Subscription databases from 2013 SQL
4. Restore in 2016 SQL
5. Create new App Management and Subscription Service Applications using the restored service DB names.
6. Mount 2013 content database to the web application.
7. Create App Web URL

Note that the web application URL and the App URLs are different only because we are doing a test to production model. 2013 is still in production at the moment. So 2013 (prod) has, let's say app.appdomain.com, and 2016 has app.app2016domain.com

Currently none of the app parts are showing, the apps are seen in the "View all Site Content", but you can't upgrade them, and you can't browse to their app webs, and when adding a new app they aren't shown.

Also...where is the microsoft documentation for migrating apps?

Answer 1

Take this as some form of documentation. Turns out it was because I was using host named site collections, and upon mounting, the web application default url that I mounted it to had the same URL, so it thought it was a path based, which made the web application work fine, but the apps weren't registering.

If you are migrating a host named site collection, make sure that you mount it from a base web application, with a root site collection. I can't take credit for this though. My colleague pointed me in the right direction.

• Create App Management and Subscription Settings Service Applications with the same restored service dbs from 2013.
• Set-SPAuthenticationRealm -Realm "<guid>" where the guid is the same spauthenticationrealm as the 2013 farm
• Important....You MUST use the same web application URL. The webapplication url I use is irrelevant because the root just hosts all the HNSC. I tried changing it after the fact and it seemed all okay.
• Create new app site catalog and install/upload all the apps
• Mounted the Team Site content db (did this first since this is the root HNSC)
• used $spsite.Rename() to change the HNSC URL to the test url
• ((Get-SPSite <siteurl>).ContentDatabase).RefreshSitesInConfigurationDatabase()
• iisreset on web front ends
• Configure App URL if you haven't already (should be a forward lookup zone that points to your FE or a VIP to both/all front ends.

My application came up and the apps were all there with all of the apps and app parts showing just fine. If you use the ...(ellipis) on the App in the Site Contents, you should see the "About" section.

Answer 2

Answering last question first: It looks like Microsoft fully missed the migration-path for addins. I have looked several times for it and never found any information.

Try to skip steps 1 (Create app catalog) and 2 (Upload/Install apps). Instead migrate the AppCatalog from 2013 environment. I think you break relationship between AppCatalog (new created) and AppManagementService (migrated).

I posted some related questions, maybe they point you to the right direction:
Upgrade High-Trust Addin/App from 2013 to 2016
Migrate SharePoint App-Domain from 2013 to 2016