Recently had to update the .NET Framework version for a service. Initially, did a quick and dirty regex replace:

$projectPaths = Get-ChildItem -include *.csproj -Recurse -Path $Path
(Get-Content $_.FullName) -Replace '<TargetFramework(s)?>.*', $targetFrameworkTag | Set-Content $_.FullName

Here is a more robust script with an option to use XmlDocument and XPath :

Summary

• This script can be updated to update other tags/properties.

• Use the -replace parameter/flag that supports regular expressions as opposed to the String.Replace() which does not.

• Double-check your regex pattern for anchors (specifically ^) when there shouldn't be in this scenario.

• Ensure encoding is set to what you expect for both XmlDocument.Save() and Set-Content.

References

• https://learn.microsoft.com/en-us/dotnet/standard/frameworks

• https://regex101.com/

• https://stackoverflow.com/questions/63476408/powershell-xmldocument-save-as-utf-8-without-bom