Starting in November 2018, the Azure PowerShell Az module is available for full public preview. Az offers shorter commands, improved stability, and supports Windows, macOS, and Linux. Az also offers feature parity and an easy migration path from AzureRM.
Az uses the .NET Standard library, which means it runs on PowerShell 5.x and PowerShell 6.x. Since PowerShell 6.x can run on Linux, macOS, and Windows, that means Az is available for all platforms. Using .NET Standard allows us to unify the code base of Azure PowerShell with minimal impact on users.
Az is a new module, so the version has been reset. The first stable release will be 1.0, but the module has feature parity with AzureRm as of November 2018.