Missing docs: `SubsystemVersion` changed to 6.00 starting with .NET 4.5

[Sarsagigis]

Type of issue

Missing information

Description

The migration guide for .NET Framework 4.5.x does not mention that the default SubsystemVersion changed from 4.00 to 6.00 starting with .NET 4.5.

This change is a potential breaking change for some applications (e.g., causing unexpected WinForms size changes), but the documentation completely lacks any reference to it or the <SubsystemVersion>4.00</SubsystemVersion> workaround.

For example, applications that (manually) calculate and set form sizes using properties like SystemInformation.FixedFrameBorderSize (or other properties which are based on the WinAPI GetSystemMetrics) can experience layout issues.

Suggested Changes

Add a section under .NET Framework 4.5 retargeting changes to document this change, its potential impact on window layout calculations and/or SystemInformation class, and possible workarounds (e. g. setting <SubsystemVersion>4.00</SubsystemVersion> in MSBuild project file).

Supporting Documentation and Additional References

• Form height and width changes with Visual Studio 2012
• Advanced C# compiler options - SubsystemVersion
• SystemInformation Class (System.Windows.Forms)
• StackOverflow - GetSystemMetrics() returns different results for .NET 4.5 & .NET 4.0

Page URL

https://learn.microsoft.com/en-us/dotnet/framework/migration-guide/retargeting/4.5.x

Content source URL

https://github.com/dotnet/docs/blob/main/docs/framework/migration-guide/retargeting/4.5.x.md

Document Version Independent Id

5dffbe36-6484-a776-9883-c6e7a1012393

Platform Id

ccf0f030-71d9-2cf8-aa89-f53eb90613d7

Article author

@chlowell

Metadata

• ID: c2cfe5e7-6f4e-9602-427f-b2426327d869
• PlatformId: ccf0f030-71d9-2cf8-aa89-f53eb90613d7
• Service: dotnet-framework

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