Jetpack: WordPress 5.3 Compatibility

[jeherve]

WordPress 5.3 is currently scheduled to ship November 12 2019, and will include changes that we should aim to support in Jetpack.

I am creating this Master Issue to help me keep track of all those changes:

• [x] Date/Time functionality changes #13513
• [x] Block Editor: support block previews #13510
• [x] Themes: full compatibility with Twenty Twenty #13511
• [x] Carousel: support Gallery block markup changes #13582
• [x] SSO: Login form changes #13551
• [x] Visual regressions in blocks #13618
• [x] API: ensure compatibility with spread operator changes in WP 5.3 #13694
• [x] Photon: Ensure compat and optimizations with 5.3 #13701
• [x] Calypsoify: update to be compatible with WordPress 5.3 admin CSS changes #13704
• [x] Dashboard: update Jetpack button and card styles to match WordPress 5.3 #13729
• [x] Widgets: add aria-current attribute to links when on same page #13831

[simison]

Might need reviewing: https://make.wordpress.org/core/2019/10/09/wp-5-3-introducing-the-spread-operator/

[jeherve]

@simison Good Call. Noted in #13694

[kraftbj]

Only slightly related but we can get a tiny performance boost by using the spread operator ourselves: https://github.com/Automattic/jetpack/pull/13699

The most gain would be to XML-RPC but we can't optimize that until Core does since we extend their IXR classes.

[simison]

Is this listenTo affected by https://make.wordpress.org/core/2019/10/10/wordpress-5-3-backbone-upgrade-guide/?

[jeherve]

@simison No, it seems okay in my tests. 👍

[jeherve]

https://make.wordpress.org/core/2019/10/15/changes-to-wp_die-html-output-in-wordpress-5-3/

With WordPress 5.3, error messages are wrapped in a <div> rather than a <p>

This doesn't seem to impact us. 👍