Box 1: Docker container -
A custom handler can be deployed to every Azure Functions hosting option. If your handler requires operating system or platform dependencies (such as a language runtime), you may need to use a custom container. You can create and deploy your code to Azure Functions as a custom Docker container.
Box 2: PowerShell core -
When creating a function app in Azure for custom handlers, we recommend you select .NET Core as the stack. A "Custom" stack for custom handlers will be added in the future.
PowerShell Core (PSC) is based on the new .NET Core runtime.
Box 3: 7.0 -
On Windows: The Azure Az PowerShell module is also supported for use with PowerShell 5.1 on Windows.
On Linux: PowerShell 7.0.6 LTS, PowerShell 7.1.3, or higher is the recommended version of PowerShell for use with the Azure Az PowerShell module on all platforms.
Reference:
https://docs.microsoft.com/en-us/azure/azure-functions/functions-create-function-linux-custom-image https://docs.microsoft.com/en-us/powershell/azure/install-az-ps?view=azps-7.1.0