# What's new?

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Modernized update guides and Experiment examples</strong></td><td>With the experience of the last few years, we have <a href="updating/historical-overview">revised our guides for converting legacy extensions</a> to WebExtensions. The information is now more compact and the examples have also been made clearer.</td><td></td><td></td></tr><tr><td><strong>Introducing the menu typed action button</strong></td><td>Since Thunderbird 115, all our action buttons can be defined as menus:</td><td><p><img src="https://1163303201-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-L_nKoWlOPz_rkC_kHdV%2Fuploads%2Fgit-blob-cb74b70fc692ed95ff3c3bd7275eafaf28940e6a%2Fimage%20(3).png?alt=media" alt="" data-size="original"></p><p><br>See our <a href="https://github.com/thunderbird/webext-examples/tree/master/manifest_v2/menuActionButton">example</a> for more details.</p></td><td></td></tr><tr><td><strong>Support for Manifest Version 3</strong></td><td>Thunderbird 128 ESR is the first Thunderbird release to officially support <a href="whats-new/manifest-v3">Manifest V3</a>. A guide to convert extensions from Manifest V2 to Manifest V3 can be found in our <a href="https://webextension-api.thunderbird.net/en/mv3/guides/manifestV3.html">WebExtension API documentation</a>.</td><td><br></td><td></td></tr><tr><td><strong>Updated sample extensions to Manifest Version 3</strong></td><td>We updated our <a href="https://github.com/thunderbird/webext-examples">sample extensions</a> to be compatible with MV3. Each extension includes comments to highlight the required changes.</td><td></td><td></td></tr></tbody></table>