Release notes for 1.21 preview release

Author: VesaJuvonen

docs/images/121-release-notes/card-personalization.png

@@ -0,0 +1,90 @@
+---
+title: SharePoint Framework v1.21 release notes
+description: Release notes for the SharePoint Framework v1.21 release.
+ms.date: 03/03/2025
+ms.localizationpriority: high
+---
+# SharePoint Framework v1.21 release notes
+
+This release focuses primarily on the new features within the [Microsoft Viva Connections](./viva/overview-viva-connections.md) side with two key new capabilities: new data visualization options for Card Views and HTML Quick View option for Viva Connections Quick Views.
+
+[!INCLUDE spfx-release-beta]
+
+beta.0 **Released:** Feburary 25, 2025
+
+[!INCLUDE [spfx-release-notes-common](../../includes/snippets/spfx-release-notes-common.md)]
+
+## Install the latest version
+
+Install the latest generally available release of the SharePoint Framework (SPFx) by using the **@next** tag
+
+```console
+npm install @microsoft/generator-sharepoint@next --global
+```
+
+## Upgrading projects from the SPFx v1.20 to v1.21 preview version
+
+In the project's **package.json** file, identify all SPFx v1.20 packages. For each SPFx package:
+
+1. Uninstall the existing v1.20 package:
+
+    ```console
+    npm uninstall @microsoft/{spfx-package-name}@1.20
+    ```
+
+1. Install the new v1.21 preview package:
+
+    ```console
+    npm install @microsoft/{spfx-package-name}@next --save --save-exact
+    ```
+
+[!INCLUDE [spfx-release-upgrade-tip](../../includes/snippets/spfx-release-upgrade-tip.md)]
+
+## New features and capabilities
+
+### Flexible layout configuration options for web parts
+
+New flexible layout sizing options are introduced for the web part manifest. These cawn be used to adjust the default behaviour for the custom web parts as they are used within flexible layouts.
+
+```json
+  "flexibleLayoutSizing": {
+    "supportsDynamicResizing": true,
+    "defaultRowHeight": 10,
+    "defaultColumnWidth": 10
+  }
+```
+
+> [!NOTE]
+> By default all custom web parts are supported in the flexible layout option and do not require any code level changes.
+
+![Flexible layout support](../images/121-release-notes/flex-layout.png)
+
+### Viva Connections card personalization support
+
+Viva Connections will start supporting end user configuration options for the dashboard. End users can add and remove cards from the dasbhoard based on their preference. Supported cards are explictly enabled for this scenario and also custom cards are supported.
+
+By default personalization is not allowed for the custom Viva Connections cards.
+
+```json
+  "personalization": [
+    "Disallow"
+  ]
+```
+
+### Updating Teams JS SDK
+
+Default [Teams JavaScript SDK](https://github.com/OfficeDev/microsoft-teams-library-js) version for the SPFx powered solutions has been updated to version 2.32.
+
+## Deprecations
+
+No new updates.
+
+## Fixed Issues
+
+No new updates.
+
+## Feedback and issues
+
+We're interested on your feedback around the release. Do let us know any findings or other feedback using the [SPFx issue list](https://github.com/SharePoint/sp-dev-docs/issues).
+
+Happy coding! Sharing is caring! 🧡

docs/images/121-release-notes/flex-layout.png

@@ -472,6 +472,8 @@
     items:
     - name: Overview
       href: spfx/roadmap.md
+    - name: SPFx v1.21 - February 25, 2024
+      href: spfx/release-1.21.md        
     - name: SPFx v1.20 - September 26, 2024
       href: spfx/release-1.20.md
     - name: SPFx v1.19 - April 25, 2024