How to install unsigned package on Windows 10?

[slonopotamus]

Create an unsigned MSIX package page says to use Add-AppPackage -AllowUnsigned. But there is no -AllowUnsigned option on Windows 10, as you can see here

> Add-AppxPackage .\mypackage -AllowUnsigned
Add-AppxPackage : A parameter cannot be found that matches parameter name 'AllowUnsigned'.
At line:1 char:55
+ Add-AppxPackage .\mypackage -AllowUnsigned
+                                                       ~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Add-AppxPackage], ParameterBindingException
    + FullyQualifiedErrorId : NamedParameterNotFound,Microsoft.Windows.Appx.PackageManager.Commands.AddAppxPackageCommand

[Boefdaan058]

all comments must go before the package
Add-AppPackage -allowUnsigned -path "/path/to/file"

[not-nullptr]

the given command still fails. was -AllowUnsigned removed?