Document .NET 10 OpenSSL 1.1.1 minimum requirement on Unix

[Copilot]

.NET 10 requires OpenSSL 1.1.1+ on Unix platforms using OpenSSL for cryptography (e.g., Linux). Applications fail to start if an older version is present. macOS is unaffected as it doesn't use OpenSSL.

Changes

• New breaking change document: docs/core/compatibility/cryptography/10.0/openssl-version-requirement.md

  • Documents behavioral change introduced in .NET 10 GA
  • Previous behavior: Supported OpenSSL 1.0.2, 1.1.0
  • New behavior: Requires OpenSSL 1.1.1+
  • Recommended action: Use Linux/Unix distributions with OpenSSL 1.1.1+

• Updated navigation: Added entries to toc.yml and 10.0.md index under Cryptography section

Fixes #47072

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Breaking change]: .NET 10 requires OpenSSL 1.1.1 or later on Unix</issue_title>
<issue_description>### Description

For platforms where .NET uses OpenSSL for cryptography such as Linux, OpenSSL 1.1.1 or later is required.

.NET 10 on macOS does not use OpenSSL and is not impacted.

Version

.NET 10 GA

Previous behavior

.NET applications supported OpenSSL prior to 1.1.1, such as 1.0.2 or 1.1.0.

New behavior

.NET applications require OpenSSL 1.1.1 or later. If OpenSSL 1.1.1 is not available on a platform that requires it, the application will fail to start.

Type of breaking change

• Binary incompatible: Existing binaries might encounter a breaking change in behavior, such as failure to load or execute, and if so, require recompilation.
• Source incompatible: When recompiled using the new SDK or component or to target the new runtime, existing source code might require source changes to compile successfully.
• Behavioral change: Existing binaries might behave differently at run time.

Reason for change

OpenSSL prior to OpenSSL 1.1.1 is outdated and not supported by mainstream Linux or Unix distributions. Supporting these out-of-date OpenSSL increases complexity of maintenance where that effort is better made on supporting modern versions of OpenSSL.

Recommended action

Use a distribution of Unix or Linux that includes OpenSSL 1.1.1 or later.

Feature area

Cryptography

Affected APIs

No response

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Associated WorkItem - 503001</issue_description>

Comments on the Issue (you are @copilot in this section)

@vcsjones This needs 👍 from @bartonjs for review. @bartonjs Oh, right, this is more "it's exploding, and we're going to not fix it" than "we deleted all the remaining supporting code in main".

Yeah, LGTM.</comment_new>

• Fixes [Breaking change]: .NET 10 requires OpenSSL 1.1.1 or later on Unix #49487

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Internal previews

📄 File	🔗 Preview link
docs/core/compatibility/10.0.md	Breaking changes in .NET 10
docs/core/compatibility/cryptography/10.0/openssl-version-requirement.md	.NET 10 requires OpenSSL 1.1.1 or later on Unix
docs/core/compatibility/toc.yml	docs/core/compatibility/toc

[Copilot]

Pull Request Overview

This PR documents a breaking change in .NET 10 that requires OpenSSL 1.1.1 or later on Unix platforms. The change drops support for older OpenSSL versions like 1.0.2 and 1.1.0.

• Adds documentation for the OpenSSL version requirement breaking change
• Updates the table of contents to include the new article
• Adds entry to the .NET 10 breaking changes index

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
docs/core/compatibility/cryptography/10.0/openssl-version-requirement.md	New breaking change article documenting OpenSSL 1.1.1+ requirement
docs/core/compatibility/toc.yml	Adds TOC entry for the new OpenSSL version requirement article
docs/core/compatibility/10.0.md	Adds the breaking change to the .NET 10 breaking changes index