Add no_std Release Notes

release-content/0.16/release-notes/17955_Add_no_std_support_to_bevy.md

@@ -1,4 +1,45 @@
 <!-- Add `no_std` support to `bevy` -->
 <!-- https://github.com/bevyengine/bevy/pull/17955 -->
 
-<!-- TODO -->
+Bevy now has support for `no_std` targets, allowing it to be used on a much wider range of platforms.
+
+This has been functionality [discussed] going back over 4 years, but was initially dropped to avoid the added complexity managing `no_std` support can bring.
+To be `no_std` compatible, your crate and _all_ of its dependencies must also be `no_std`.
+Coordinating that kind of support across over a hundred dependencies was just not feasible, let alone losing access to Rust's standard library.
+
+Since then, Rust's support for `no_std` has evolved dramatically with support for critical APIs such as [`Error`] coming in [Rust 1.81].
+Starting with tracking issue [#15460] and a [`no_std` Working Group], Bevy's various crates were individually made `no_std` compatible where possible.
+To aid this effort, [`bevy_platform_support`] was developed with the goal of providing opinionated alternatives to `std` items.
+
+This effort reached a substantial milestone during the development of Bevy 0.16: support for `no_std` in our main `bevy` crate.
+To use Bevy on a `no_std` platform, simply disable default features and use Bevy just like any other `no_std` dependency.
+
+```toml
+[dependencies]
+bevy = { version = "0.16", default-features = false }
+```
+
+Note that not all of Bevy's features are compatible with `no_std` yet.
+Rendering, audio, and assets are notable missing APIs that you will need to find an alternative for that's suitable for your platform.
+But, Bevy's powerful [`Plugin`] system allows the community to build back support for that functionality for their particular platforms.
+
+For those community members working on libraries for Bevy, we encourage you to try out `no_std` support if you can!
+There's a new [`no_std` library] example which demonstrates how to make a crate that is compatible with `std` and `no_std` users, with detailed comments and advice.
+During the release candidate period, quite a few libraries have successfully experimented with `no_std` support, such as [`bevy_rand`] and [`bevy_replicon`].
+
+Determining what `no_std` targets support Bevy is still a work in progress.
+But early reports from users have shown Bevy working on bare-metal desktops, embedded devices, and even retro consoles such as the GameBoy Advance.
+
+If you have an unusual platform you'd like to try getting Bevy working on, check out the [`#unusual-platforms`] channel on Bevy's Discord server for advice!
+
+[`Error`]: https://doc.rust-lang.org/stable/core/error/trait.Error.html
+[#15460]: https://github.com/bevyengine/bevy/issues/15460
+[`no_std` Working Group]: https://discord.com/channels/691052431525675048/1303128171352293410
+[`bevy_platform_support`]: https://crates.io/crates/bevy_platform_support/
+[`#unusual-platforms`]: https://discord.com/channels/691052431525675048/1284885928837517432
+[discussed]: https://github.com/bevyengine/bevy/discussions/705
+[`Plugin`]: https://docs.rs/bevy/latest/bevy/app/trait.Plugin.html
+[Rust 1.81]: https://releases.rs/docs/1.81.0/#stabilized-apis
+[`no_std` library]: https://github.com/bevyengine/bevy/tree/main/examples/no_std/library
+[`bevy_replicon`]: https://github.com/projectharmonia/bevy_replicon/tree/bevy-0.16-dev
+[`bevy_rand`]: https://github.com/Bluefinger/bevy_rand