docs: 0.31.1 release notes

Author: jacobcreech

docs/content/docs/updates/changelog.mdx

@@ -9,6 +9,19 @@ patch version will be incremented for features.
 
 ---
 
+## [0.31.1] - 2025-04-19
+
+### Features
+
+ - ts: Make `Provider` require publicKey instead of wallet in accounts resolver ([#3613](https://github.com/coral-xyz/anchor/pull/3613))
+
+### Fixes
+
+- idl: Update `proc-macro2` usage for latest nightly ([#3663](https://github.com/solana-foundation/anchor/pull/3663))
+- cli, docker: Replace `backpackapp/build` Docker image with `solanafoundation/anchor` ([#3619](https://github.com/coral-xyz/anchor/pull/3619)).
+
+### Breaking
+
 ## [0.31.0] - 2025-03-08
 
 ### Features

docs/content/docs/updates/release-notes/0-31-1.mdx

@@ -0,0 +1,70 @@
+---
+title: 0.31.1
+description: Anchor - Release Notes 0.31.1
+---
+
+This release uses a new docker image found at `solanafoundation/anchor` for the `anchor verify` command. New images will be pushed to this organization in the future.
+
+Releases for anchor will also be published under the `solanafoundation` Github organization from now on.
+
+As always, there are a great number of changes, but we'll only be covering the
+most important ones here. For a list of all notable changes, see the
+[CHANGELOG](https://github.com/coral-xyz/anchor/blob/v0.31.1/CHANGELOG.md#0311---2025-04-19).
+
+### IDL Build Fixes
+
+As of `nightly-2025-04-16`, `SourceFile` does not exist anymore. 
+IDLs have been historically built with nightly, and in order to fix this we had 
+to update our `proc_macro2` usage accordingly.
+
+If you ran into the following error whild building:
+
+```
+no method named `source_file` found for reference `&proc_macro::Span` in the current scope
+```
+
+This should now be fixed in this release.
+
+
+---
+
+## How to upgrade
+
+1. Install the latest version of `avm`:
+
+   ```sh
+   cargo install --git https://github.com/coral-xyz/anchor avm --force
+   ```
+
+   This will allow installing Anchor CLI without having to compile from source,
+   see [Install from binary](#install-from-binary).
+
+2. Update `anchor-cli`:
+
+   ```sh
+   avm install 0.31.1
+   ```
+
+3. Update Anchor crate(s) to `0.31.1`.
+
+4. Update TS package(s) to `0.31.1`.
+
+## Recommended Solana Version
+
+The recommended Solana version is `2.1.0`. This is a special upgrade because
+some of the Solana binaries have been renamed to Agave, see
+[Agave transition](https://github.com/anza-xyz/agave/wiki/Agave-Transition).
+
+You can install the newer tooling by running:
+
+```
+sh -c "$(curl -sSfL https://release.anza.xyz/v2.1.0/install)"
+```
+
+This change is handled automatically if you specify `toolchain.solana_version`,
+see [Automatic Agave transition](#automatic-agave-transition).
+
+---
+
+See the full list of notable changes in the
+[CHANGELOG](https://github.com/solana-foundation/anchor/blob/v0.31.1/CHANGELOG.md#0311---2025-04-19).

docs/content/docs/updates/release-notes/meta.json

@@ -1,4 +1,4 @@
 {
   "title": "Release Notes",
-  "pages": ["0-31-0", "0-30-1", "0-30-0", "0-29-0"]
+  "pages": ["0-31-1", "0-31-0", "0-30-1", "0-30-0", "0-29-0"]
 }