Merge 9efb3f33bc into 638ed79f9d

Add note on runner versions

README.md

@@ -19,16 +19,19 @@ See ["Caching dependencies to speed up workflows"](https://docs.github.com/en/ac
 
 The cache backend service has been rewritten from the ground up for improved performance and reliability. [actions/cache](https://github.com/actions/cache) now integrates with the new cache service (v2) APIs.
 
-The new service will gradually roll out as of **February 1st, 2025**. The legacy service will also be sunset on the same date. Changes in these release are **fully backward compatible**.
+The new service will gradually roll out as of **February 1st, 2025**. The legacy service will also be sunset on the same date. Changes in these releases are **fully backward compatible**.
 
 **We are deprecating some versions of this action**. We recommend upgrading to version `v4` or `v3` as soon as possible before **February 1st, 2025.** (Upgrade instructions below).
 
-If you are using pinned SHAs, please use the SHAs of versions `v4.2.0` or `v3.4.0`
+If you are using pinned SHAs, please use the SHAs of versions `v4.2.0` or `v3.4.0`.
 
 If you do not upgrade, all workflow runs using any of the deprecated [actions/cache](https://github.com/actions/cache) will fail.
 
 Upgrading to the recommended versions will not break your workflows.
 
+> **Additionally, if you are managing your own GitHub runners, you must update your runner version to `2.231.0` or newer to ensure compatibility with the new cache service.**  
+> Failure to update both the action version and your runner version may result in workflow failures after the migration date.
+
 Read more about the change & access the migration guide: [reference to the announcement](https://github.com/actions/cache/discussions/1510).
 
 ### v4
@@ -209,6 +212,9 @@ A cache key can include any of the contexts, functions, literals, and operators
 
 For example, using the [`hashFiles`](https://docs.github.com/en/actions/learn-github-actions/expressions#hashfiles) function allows you to create a new cache when dependencies change.
 
+> [!NOTE]  
+> The cache key is rendered during the restore stage, so can only depend on file state at that stage.
+
 ```yaml
   - uses: actions/cache@v4
     with: