nixos/doc/rl-2411: warn about upcoming macOS version requirement (#33…

…8695)

nixos/doc/manual/release-notes/rl-2411.section.md

@@ -4,6 +4,12 @@
 
 ## Highlights {#sec-release-24.11-highlights}
 
+- **This will be the latest version of Nixpkgs to support macOS 10.12 (Sierra).**
+  Starting with release 25.05, the minimum supported version will be macOS 11 (Big Sur).
+  From that point on, packages may or may not work on older releases of macOS.
+  Users on old macOS versions should consider upgrading to a supported OS release (potentially using [OpenCore Legacy Patcher](https://dortania.github.io/OpenCore-Legacy-Patcher/) for old hardware) or installing NixOS.
+  If neither of those options are viable and you require new versions of software, [MacPorts](https://www.macports.org/) supports back to OS X 10.6 (Snow Leopard).
+
 - Convenience options for `amdgpu`, open source driver for Radeon cards, is now available under `hardware.amdgpu`.
 
 - [AMDVLK](https://github.com/GPUOpen-Drivers/AMDVLK), AMD's open source Vulkan driver, is now available to be configured as `hardware.amdgpu.amdvlk` option.