Pragmatic approach to push update of Add-In when via SharePoint UI fails

In previous blogpost, I recalled on a malforming COTS Add-In. Once the supplier delivered a fix, our SharePoint IT Operations team executed a change to update the Add-In version in the SharePoint environment. First upload the new version to the SharePoint AppCatalog, and next update the installed Add-In in the using SharePoint site(s). Both steps can be done via the SharePoint GUI, the second via the 'Get It' capability. The operations teams verified the deployment approach first in the acceptance environment, and validated that the problem with Add-In was resolved. All well. However, during the change execution in the productive environment, a problem was raised on the 'Get It' step to update the Add-In installation in the using site: Sorry apps are turned off. if you know who runs the server tell them to enable apps. I first told them to verify that both App Management Service and Subscription Settings Services were (still) enabled on the SharePoint webapplication. On the positive answer, I then concluded the problem to be likely as a glitch in the SharePoint site. The Add-In itself namely was unlikely to have a deployment problem, as we earlier successful updated the deployed installation in the acceptance farm. Thinking out-of-the-box, I next advised the IT Operations team to retry the Add-In update through PowerShell iso via the SharePoint GUI. Either it would work, or otherwise a bigger chance of getting meaningful error information. In our case, the former was true: via PowerShell the Add-In update was successful pushed in the using SharePoint site.

PowerShell snippet:

 $web = Get-SPWeb ‘https://<site-url>’
 $appPackage = Import-SPAppPackage -Path ‘<Add-In deployment package>.app’ -Site $web.Site -Source ‘CorporateCatalog’  -Confirm:$false
 $curAppInstall = Get-SPAppInstance -Web $web | where Title -eq ‘<Add-In title>’
 
 Update-SPAppInstance -Identity $curAppInstall -App $appPackage -ErrorAction SilentlyContinue -ErrorVariable err
 if($err)
 {
     $err[0].Exception
 }