PowerShell Versions 5.1 and 7+: Why Are There Two Main Versions?
If you’ve worked with PowerShell for any length of time, you may have come across two distinct versions: PowerShell 5.1 and PowerShell 7+. It can be a bit confusing at first glance, especially if you’re used to dealing with software that simply progresses in numerical order. Why then, do we have these two versions running side by side? To answer that, we need to delve into the history and evolution of PowerShell itself.
PowerShell 5.1: The End of an Era
PowerShell 5.1 is the last release of Windows PowerShell, which was first introduced as an automation and configuration management framework built on the .NET Framework. Originally developed as a Windows-only tool, PowerShell was designed to help administrators automate a range of tasks, from managing file systems to handling services and processes across Windows environments.
By the time version 5.1 came along, PowerShell had matured into a robust and versatile scripting language. It featured deep integration with Windows, supported remoting, had a host of useful cmdlets (commands), and provided easy access to the underlying operating system. However, the key limitation was its confinement to Windows. Since it was built on the .NET Framework, it couldn’t easily be ported to other platforms.
For many users who work exclusively with Windows, PowerShell 5.1 continues to be highly relevant. It remains the default version on many Windows systems, and its tight coupling with Windows technologies like Active Directory and Windows Management Instrumentation (WMI) makes it indispensable in certain scenarios. For example, if you’re working in a Windows-only environment with legacy systems, PowerShell 5.1 might still be your go-to.
PowerShell 7+: The Cross-Platform Revolution
Now, if PowerShell 5.1 was the culmination of its Windows-centric era, PowerShell 7+ represents a new chapter entirely. Starting with PowerShell 6, Microsoft made the decision to break free from the confines of the Windows ecosystem by building on the .NET Core framework, rather than the full .NET Framework.
This shift opened up a world of possibilities. Because .NET Core is cross-platform, PowerShell 7+ is able to run on Windows, macOS, and various Linux distributions. This was a significant leap forward for users working in diverse environments or for organisations that had embraced a mix of operating systems.
PowerShell 7+ also introduced a range of improvements over version 5.1. Not only is it faster and more efficient, but it also includes new features like parallel execution with ForEach-Object -Parallel, pipeline enhancements, and compatibility with existing Windows PowerShell modules via a Windows Compatibility Pack.
Why Two Versions?
The reason we have both versions—5.1 and 7+—running in parallel is largely due to their different foundations. PowerShell 5.1 is tied to the full .NET Framework, which is Windows-only. PowerShell 7+, however, is built on .NET Core/.NET 5 and beyond, allowing it to be cross-platform.
For users, this means you can continue to use PowerShell 5.1 where it’s most appropriate (in legacy or Windows-exclusive environments) while adopting PowerShell 7+ for modern, cross-platform workflows. Microsoft continues to support both, although the active development of new features and innovations is focused on the 7+ branch.
