Version 4.0.0

ElasticPress 4.0 contains some important changes. Make sure to read these highlights before upgrading:

• This version requires a full reindex.
• It introduces a new search algorithm that may change the search results displayed on your site.
• A new feature called "Instant Results" is available. As it requires a full reindex, if you plan to use it, we recommend you enable it first and reindex only once.
• Users upgrading from Beta 1 need to re-save the Instant Results feature settings.
• New minimum versions are:

  	Min	Max
  Elasticsearch	5.2	7.10
  WordPress	5.6+	latest
  PHP	7.0+	latest

Note that ElasticPress 4.0.0 release removes built assets from the develop branch, replaced master with trunk, added a ZIP with the plugin and its built assets in the GitHub Releases page, and included a build script should you want to build assets from a branch. As such, please plan to update any references you have from master to trunk or to GitHub Releases depending on whether you require built assets or not. (See changes in #2622.)

The Facets widget is not currently available within Full Site Editing mode.

This changelog contains all changes made since 3.6.6 (including Beta 1.)

Added

• Instant Results. Props @JakePT, @felipeelia, and Pratheep Chandrasekhar via #2481 and #2500.
• New default search algorithm prioritizing exact matches, matches in the same field, then matches across different fields. Props @brandwaffle and @felipeelia via #2498.
• Filter ep_load_search_weighting to disable search weighting engine. Props @rebeccahum and @felipeelia via #2522.
• Post types to facet labels when needed to to differentiate facets with duplicate labels. Props @JakePT and @felipeelia via #2541.
• Support for search form post type fields to Instant Results. Props @JakePT via #2510.
• Alternative way to count total posts on larger DBs during indexing. Props @rebeccahum and @felipeelia via #2571.
• Do not count posts in get_total_objects_for_query_from_db() if any object limit IDs are passed in. Props @rebeccahum via #2586.
• Show WP-CLI progress on the new Sync page. Props @Rahmon and @felipeelia via #2564.
• Display results counts for facet options in Instant Results. Props @JakePT, @felipeelia via #2563.
• ARIA attributes to Facet widget links to improve accessibility. Props @JakePT via #2607.
• Support for shareable URLs to Instant Results. Props @JakePT and @felipeelia via #2604.
• Dynamic bulk requests limits. Instead of sending only one request per document batch, send several adjusting their sizes based on the Elasticsearch response. Props @felipeelia, @dinhtungdu, @brandwaffle, and @Rahmon via #2585.
• New step in the installation process: users can now select features before the initial sync. Props @felipeelia, @JakePT, Jonathan Netek, and @brandwaffle via #2572.
• Complement to the resync message related to Instant Results. Props @felipeelia and @brandwaffle via #2628.

Changed

• Sync page and code responsible for indexing. Props @helen, @felipeelia, @Rahmon, @mckdemps, @tott, and Pratheep Chandrasekhar via #1835, #2448, and #2501.
• When Protected Content is enabled, ElasticPress will have a more similar behavior to WordPress core but the post content and meta will not be indexed (the new ep_pc_skip_post_content_cleanup can be used to skip that removal.) Props @rebeccahum, @oscarssanchez, @felipeelia, @dinhtungdu, @cristianuibar, and @allan23, @mallorydxw via #2408 and #2646.
• Bump minimum required versions of Elasticsearch from 5.0 to 5.2 and WordPress from 3.7.1 to 5.6. Props @felipeelia via #2475.
• Bump minimum required PHP version from 5.6 to 7.0. Props @felipeelia, @ActuallyConnor, and @brandwaffle via #2485 and #2626.
• Internationalize start and end datetimes of sync. Props @Rahmon and @felipeelia via #2485 and #2548.
• ep_integrate argument in WP_Query to accept 0 and 'false' as valid negative values. Props @oscarssanchez, @Rahmon, and @felipeelia via #2547 and #2573.
• To comply with modern WooCommerce behavior, ElasticPress no longer changes the orderby parameter. Props @felipeelia and @beazuadmin via #2577.
• Query parameters for facets to start with ep_filter, changeable via the new ep_facet_filter_name filter. Props @oscarssanchez, @felipeelia, and @slaxxarn via #2560.
• Output of sync processes using offset to display the number of documents skipped. Props @oscarssanchez, @felipeelia, @cbratschi, and @brandwaffle via #2591.
• Switched from WP Acceptance to Cypress for end to end tests. Props @felipeelia, @Sidsector9, and @dustinrue via #2446 and #2615.
• CSS vars usage in the new Sync page. Props @Rahmon, @JakePT, @mehidi258, and @felipeelia via #2561.
• Features screen: improved accessibility and jQuery dependency removal. Props @JakePT via #2503.
• Taxonomy parameters now reflect the WordPress parsed tax_query value. Props @felipeelia and @sathyapulse via #2419.
• Features order in the Features screen. Props @felipeelia and @brandwaffle via #2618.
• WooCommerce's search parameter also to be used by ElasticPress queries. Props @felipeelia, @dianfishekqi, and @oscarssanchez via #2620.
• Posts are now reindexed when a new term is associated with them and also when an associated term is updated or deleted. Props @nickdaugherty, @felipeelia, @brandon-m-skinner, @mckdemps, @rebeccahum via #2603.
• Updated jsdoc from 3.6.9 to 3.6.10 and fixed the documentation of the ep_thumbnail_image_size filter. Props @felipeelia via #2639.
• Instant Results: type and initial value of search template and move save to the end of sync. Props @felipeelia and @oscarssanchez via #2645.

Removed

• Built assets (minified JavaScript and CSS files) from the repository. Props @felipeelia and @jeffpaul via #2486.
• Duplicate case 'description': from ElasticPress\Indexable\Term\Term::parse_orderby. Props @sjinks via #2533.

Fixed

• CSS issues on Features page. Props @JakePT via #2495.
• AJAX URL on subsites. Props @Rahmon via #2501.
• PHP Notice while monitoring a WP-CLI sync in the dashboard. Props @felipeelia and @ParhamG via #2544.
• Sync page when WooCommerce's "hide out of stock items" and Instant Results are both enabled. Props @felipeelia via #2566.
• PHPUnit Tests and WordPress 5.9 compatibility. Props @felipeelia via #2569.
• WooCommerce Orders Search when searching for an order ID. Props @felipeelia via #2554.
• Code standards. Props @felipeelia via #2574 and #2578.
• Posts insertion and deletion in the same thread. Props @felipeelia and @tcrsavage via #2575.
• Invalid values in tax_query terms resulting in a query failure. Props @rinatkhaziev and @felipeelia via #2576 and #2583.
• New Sync Page to display a message when an indexing is stopped by the WP-CLI stop-indexing command. Props @Rahmon, @felipeelia, and @brandwaffle via #2549.
• Nested queries are no longer deleted. Props @oscarssanchez and @christianc1 via #2567.
• Type hints for epwr_decay and epwr_weight hooks. Props @edwinsiebel via #2537.
• Errors count in the new Sync page. Props @felipeelia via #2590.
• Multisite could index posts from a disabled indexing site. Props @oscarssanchez, @chrisvanpatten, @felipeelia via #2621.
• New sync code and the upper-limit-object-id and lower-limit-object-id parameters in WP-CLI command. Props @felipeelia via #2634.
• Sync link on index health page. Props @JakePT via #2644.
• Logic checking if it is a full sync and if search should go or not through ElasticPress. Props @felipeelia and @JakePT via #2642.

Security

• Use most recent external GitHub Actions versions. Props @felipeelia and @qazaqstan2025 via #2535.
• Updated 10up-toolkit from 1.0.13 to 3.0.1, jsdoc from 3.6.7 to 3.6.9, terser-webpack-plugin from 5.2.4 to 5.3.0, @wordpress/env from 4.1.1 to 4.2.2, and promise-polyfill from 8.2.0 to 8.2.1. Props @felipeelia via #2559, #2611, and #2631.
• Bumped follow-redirects from 1.14.7 to 1.14.9. Props @dependabot via #2609.

See: https://github.com/10up/ElasticPress/milestone/58?closed=1