Upcoming Az modules breaking change

> **NOTE: Function apps using PowerShell 7 on Windows Consumption are *not* impacted, no action required.**

## Change

The upcoming versions of Az modules may not work correctly on older versions of PowerShell. For more details, see the [Azure PowerShell announcement](https://github.com/Azure/azure-powershell/issues/15035).

## Impact

The following PowerShell Function apps may be impacted:
- PowerShell 6 apps (on any SKU) that don't pin Az.Accounts to version 2.2.8 or earlier, or use Az version 6.\* or higher.
- PowerShell 7 apps on custom Linux containers with any Function Host version lower than 3.0.15584.

Function apps using PowerShell 7 on Windows Consumption are *not impacted*, no action required.

## Action required

- For PowerShell 6 apps on any SKU:
- *Highly recommended*:
- Migrate your PowerShell Function app to PowerShell 7 (for the details, refer to [PowerShell 6 to 7 Migration Guide · Azure/azure-functions-powershell-worker Wiki (github.com)](https://github.com/Azure/azure-functions-powershell-worker/wiki/PowerShell-6-to-7-Migration-Guide)).
- If you are using custom Linux containers, make sure the Functions Host version is 3.0.15584 or higher.

- If you *must* continue using PowerShell 6:
- Do *not* use Az version 6.\* or higher. For example, make sure your `requirements.psd1` does *not* contain `'Az' = '6.*'`.
- Make sure you pin the Az.Accounts module to version 2.2.8 or lower (please use the following instructions: [Target specific versions | Microsoft Docs](https://docs.microsoft.com/en-us/azure/azure-functions/functions-reference-powershell?tabs=portal#target-specific-versions)).

- For PowerShell 7 apps on custom Linux containers:
- Make sure the Functions Host version is 3.0.15584 or higher.

## PowerShell 6 support note

Please note that, even though Azure Functions using PowerShell 6 are still supported by the Azure Functions service, PowerShell 6.2 has reached its end of life as of September 4, 2020, and the Az PowerShell modules are not supported on any version of PowerShell 6. Please refer to [Supported environments](https://github.com/MicrosoftDocs/azure-docs-powershell/blob/master/azps-6.0.0/azureps-support-lifecycle.md#supported-environments) for more details.

We strongly recommend Azure Functions users to [migrate PowerShell 6 apps to PowerShell 7](https://github.com/Azure/azure-functions-powershell-worker/wiki/PowerShell-6-to-7-Migration-Guide). This migration is almost always straightforward and safe.

Start by reviewing the issue text and the linked Azure PowerShell announcement, then check the referenced PowerShell 6-to-7 migration and targeted-version guidance. The payload names no repository files, tests, or concrete documentation change, so the required scope and definition of done need to be established first.

Written by the indexing model from the issue text.