No new hooks added in 7.3.1 Below are recently added.

    sharing_ajax_action

    hook (filter): Filter the Sharing buttons' Ajax action name Jetpack checks for.<p>This allows the use of the buttons with your own Ajax implementation.</p>

    Source: modules/sharedaddy/sharing-service.php:761

    tweet_shortcode_pending_tweet

    hook (filter): Filter the default display when a tweet is not available in the store.<p>Not available in Jetpack.</p>

    Source: modules/shortcodes/tweet.php:191

    brightcove_dimensions

    hook (filter): Filter the Brightcove shortcode parameters.

    Source: modules/shortcodes/brightcove.php:76

    grunion_after_message_sent

    hook (action): Fires an action hook right after the email(s) have been sent.

    Source: modules/contact-form/grunion-contact-form.php:2810

    jetpack_video_sitemap_default_thumbnail

    hook (filter): Filter the thumbnail image used in the video sitemap for non-VideoPress videos.

    Source: modules/sitemaps/sitemap-builder.php:1334

    jetpack_sync_import_start

    hook (action): Used for syncing the start of an import

    Source: sync/class.jetpack-sync-module-import.php:95

    jetpack_wp_login

    hook (action): Fires when a user is logged into a site.

    Source: sync/class.jetpack-sync-module-users.php:184

    jetpack_sync_known_importers

    hook (filter): Filter the list of known importers.

    Source: sync/class.jetpack-sync-defaults.php:610

    jetpack_json_manage_api_enabled

    hook (filter): Filter to disallow JSON API requests to the site.<p>Setting to false disallows you to manage your site remotely from WordPress.com and disallows plugin auto-updates.</p>

    Source: json-endpoints/jetpack/class.jetpack-json-api-endpoint.php:83

    jetpack_password_checker_tests

    hook (filter): Filters Jetpack's password strength enforcement settings. You can determine the tests run and their order based on whatever criteria you wish to specify.

    Source: _inc/lib/class.jetpack-password-checker.php:278