Azure Firewall: Parallel IP Group update support is now in public preview

Multiple IP Groups for Azure Firewall can now be updated in parallel. Previously, users were required to update IP Groups sequentially. With this backend update, users can update 20 IP Groups that are referenced in a Firewall Policy at a time. This is particularly useful for administrators who want to make configuration changes more quickly and at scale, especially when making those changes using a dev ops approach (templates, ARM, CLI, and Azure PowerShell).   

Learn more in the following articles: 

Azure Firewall auto-scaling behavior 

Parallel IP Group updates (preview)