When installing PowerShell 7 on Windows, why does it remain alongside the existing Windows PowerShell 5.1 instead of replacing it? Is PowerShell 7 intended to be a direct upgrade, or is there a compatibility reason for keeping both versions installed?
3 Answers
They’re parallel products rather than simple version revisions. PowerShell 5.1 is Windows-only, whereas PowerShell 7 is designed to run on Windows, Linux, and macOS. PowerShell 7 adds newer features, but it still doesn’t provide complete compatibility with every Windows-specific cmdlet or module.
PowerShell 7 isn’t a direct upgrade to Windows PowerShell 5.1. It’s a separate, cross-platform application built on modern .NET, while Windows PowerShell 5.1 is tied to the older .NET Framework and is part of Windows. Keeping both avoids breaking existing scripts, modules, and tools that depend on the older environment.
Compatibility is the main reason. Many older scripts will work in PowerShell 7, but some Windows-specific functionality and modules won’t. For example, certain management commands can have different capabilities between 5.1 and 7, so removing 5.1 could break existing automation.

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