add blog post about docs.rs changed default targets

content/docs-rs-changed-default-targets.md

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+path = "2025/10/16/docsrs-changed-default-targets"
+title = "docs.rs: changed default targets"
+authors = ["Denis Cornehl"]
+
+[extra]
+team = "the docs.rs team"
+team_url = "https://rust-lang.org/governance/teams/dev-tools/#team-docs-rs"
++++
+
+# Changes to default build targets on docs.rs
+
+This post announces two changes to the list of default targets used to build
+documentation on docs.rs.
+
+Crate authors can specify a custom list of targets using
+[docs.rs metadata in `Cargo.toml`](https://docs.rs/about/metadata). If this
+metadata is not provided, docs.rs falls back to a default list. We are updating
+this list to better reflect the current state of the Rust ecosystem.
+
+## Apple silicon (ARM64) replaces x86_64
+
+Reflecting Apple's transition from x86_64 to its own ARM64 silicon, the Rust
+project has updated its platform support tiers. The `aarch64-apple-darwin`
+target is now Tier 1, while `x86_64-apple-darwin` has moved to Tier 2. You can
+read more about this in [RFC 3671](https://github.com/rust-lang/rfcs/pull/3671)
+and [RFC 3841](https://github.com/rust-lang/rfcs/pull/3841).
+
+To align with this, docs.rs will now use `aarch64-apple-darwin` as the default
+target for Apple platforms instead of `x86_64-apple-darwin`.
+
+## Linux ARM64 replaces 32-bit x86
+
+Support for 32-bit `i686` architectures is declining, and major Linux
+distributions have begun to phase it out.
+
+Consequently, we are replacing the `i686-unknown-linux-gnu` target with
+`aarch64-unknown-linux-gnu` in our default set.
+
+## New default target list
+
+The updated list of default targets is:
+
+- `x86_64-unknown-linux-gnu`
+- `aarch64-apple-darwin` (replaces `x86_64-apple-darwin`)
+- `x86_64-pc-windows-msvc`
+- `aarch64-unknown-linux-gnu` (replaces `i686-unknown-linux-gnu`)
+- `i686-pc-windows-msvc`
+
+## Opting out
+
+If your crate requires the previous default target list, you can explicitly
+define it in your `Cargo.toml`:
+
+```toml
+[package.metadata.docs.rs]
+targets = [
+    "x86_64-unknown-linux-gnu",
+    "x86_64-apple-darwin",
+    "x86_64-pc-windows-msvc",
+    "i686-unknown-linux-gnu",
+    "i686-pc-windows-msvc"
+]
+```
+
+Note that docs.rs continues to support any target available in the Rust
+toolchain; only the _default_ list has changed.