What’s new for developers (December 2025)

What’s new for developers? (December 2025) 🔗 **Source:** [What’s new for developers? (December 2025)](https://developer.wordpress.org/news/2025/12/whats-new-for-developers-december-2025/) > [!note]+ Document Notes > tags: [wordpress, core, playground] > author: WordPress Developer Blog > source: developer.wordpress.org > reference: [https://developer.wordpress.org/news/2025/12/whats-new-for-developers-december-2025/] > date created: 2025-12-11 10:00 > > --- > > # 🏷️ Title: What’s new for developers? (December 2025) >  ## 🧭 Table of Contents - [📝 Summary](#-summary) - [📖 Main Content](#-main-content) - [🗒️ Notes](#️-notes) - [📚 References](#-references) - [🗣️ Paraphrase](#️-paraphrase) - [📰 Newsletter](#-newsletter) - [✅ Action Items](#-action-items) - [🧪 Hypotheses](#-hypotheses) - [📊 Methodology](#-methodology) - [❓ Questions](#-questions) - [🔮 Future Research](#-future-research) - [💡 Implications](#-implications) - [🧠 Learning Styles Assessment](#-learning-styles-assessment) - [📊 Accessibility Assessment](#-accessibility-assessment) - [🌍 DEIB Assessment](#-deib-assessment) - [✅ Logical Validity](#-logical-validity) - [🛡️ DARVO Analysis](#-darvo-analysis) - [🎯 Conclusion](#-conclusion) ### 🔗 References - Include links cited in or relevant to the article. ## 📝 Summary - WordPress 6.9 “Gene” ships with major block, editor, and dev‑tool updates plus a new AI Experiments plugin and big Playground advances. - It matters because it modernizes core (e.g., removes Flash), standardizes routing, and expands the block system and AI experimentation surface. - Stakeholders: core and plugin/theme devs, agencies, hosts, and tooling vendors. - Risks: experimental APIs (tabs, breadcrumbs, contentOnly) may introduce regressions; AI integration adds complexity and policy needs. - Bottom line: upgrade, test against trunk/Gutenberg, and start using the new AI, routing, and Playground capabilities. ## 📖 Main Content - WordPress 6.9 “Gene” is released; readers are pointed to the Field Guide and State of the Word for deep dives. - A new AI Experiments plugin provides a registry, base classes, and example title-generation experiment plus settings to manage external AI providers. - Experimental Breadcrumbs and Tabs blocks land in the Gutenberg experiments package, targeting better navigation and layout flexibility. - WPCS 3.3.0 adds PHP 8.x support (including anonymous/readonly classes, `exit()` handling) and new spacing/attribute sniffs. - Core fully removes Flash-related code, simplifying the media system. - Data Views/Forms and Field API get UX and validation improvements, including column insertions, wrapper styling, pattern rules, and date formatting controls. - The `@wordpress/boot` package gains static and lazy routing for the ongoing admin redesign. - `contentOnly` template locking now allows controlled block insertion inside content regions. - Multiple block‑library enhancements land: Accordion fixes, revamped HTML block modal, Paragraph alignment support, Term Name level options, Button pseudo‑class styling via `theme.json`, video backgrounds in Cover, and improved Math block styling and directionality. - Border‑radius presets now correctly handle mixed CSS values (`clamp`, `min`, `max`, `calc`). - WordPress Playground’s 2025 recap highlights near‑universal plugin compatibility, perf gains (OpCache), modern tooling support, and new browser‑based dev features and collaboration helpers (Adminer/phpMyAdmin, live Blueprint edits, PR previews, Intl extension). - The article ends with a dev‑note index and credits to contributors. ### 🗒️ Notes - WordPress 6.9 “Gene” is framed as an end‑of‑year gift, with encouragement to read the Field Guide and watch State of the Word. - AI Experiments plugin: - Provides a small framework to “register, toggle, and iterate on experimental AI capabilities.” - Integrates with the WP AI Client SDK for external AI providers. - Ships a “Title Generation” example experiment in the editor. - Adds admin settings for credentials and feature/global toggles. - Experimental Breadcrumbs block: - Aims to make navigation clearer on complex sites. - Still requires enabling via Gutenberg → Experiments. - Targeted to stabilize early in the 7.0 cycle. - Experimental Tabs block: - Part of Gutenberg experimental blocks, enabled via Experiments. - Early‑stage; introduces attributes for pseudo‑classes/states on the Tabs block. - Already supports horizontal and vertical layouts. - WPCS 3.3.0: - Adds support for attributes on anonymous classes and readonly anonymous classes (PHP 8.0/8.3) in security sniffs. - Handles `exit` as a function call (PHP 8.4). - Adds sniffs for no inside‑bracket spacing and disallowing parentheses on attributes without parameters. - Flash removal: - WordPress 6.9 removes `swfupload`, `swfobject`, and other Flash fallbacks from the media system. - Positioned as dropping “legacy baggage” since Flash is unsupported everywhere. - Data Views & Forms: - Data Views: insert columns from header (“Insert Left/Right”), style wrapper with background color/image. - Data Forms: pattern‑based rules for validating formats. - Field API: configure date parsing/formatting on date fields. - `@wordpress/boot` routing: - Now supports static and lazy routes for more efficient loading. - Tied to admin redesign; provides a standard way for core/plugins to declare routes. - `contentOnly` template lock: - Allows inserting content blocks inside predefined content areas. - Needs extensive testing in the 7.0 cycle for compatibility. - Accordion block: - Shipped in 6.9 with high design flexibility. - A CSS tweak for Twenty Twenty‑One triggered padding overflow and a too‑specific heading toggle selector. - One fix landed in 6.9; the other is scheduled for 6.9.1. - Other block updates: - HTML block gets a fullscreen modal with separate tabs for HTML, CSS, JS. - Paragraph block moves to shared text‑align support and adds global justified alignment. - Term Name block gains `levelOptions` control. - Button block pseudo‑classes can be styled in `theme.json`. - Cover block supports embedded video (e.g., YouTube, Vimeo) as looping backgrounds. - Math block aligns design tools with other blocks and always displays LTR, even in RTL contexts. - Border radius presets: - Range slider now parses mixed CSS values correctly (e.g., `clamp()`, `min()`, `max()`, `calc()`). - Playground 2025 year in review: - 99%+ plugin compatibility. - OpCache reduces response times by 42%. - Adds Xdebug, WebP/AVIF, and other modern tooling. - New file editor, Blueprints gallery, and DB management tools in the browser. - Playground dev/testing/collab: - One‑click Adminer and phpMyAdmin for SQLite via MySQL‑style tools. - Live Blueprint editing in the browser. - GitHub Actions PR previews that spin up Playground environments. - Intl extension added to `@php-wasm/web` for better i18n. - The article closes with a dev‑notes index for 6.9 and contributor credits. ## 📚 References - [What’s new for developers? (December 2025)](https://developer.wordpress.org/news/2025/12/whats-new-for-developers-december-2025/) - [WordPress 6.9 Field Guide](https://make.wordpress.org/core/tag/6-9-field-guide/) - [WordPress 6.9 “Gene” release post](https://wordpress.org/news/) - [AI Experiments plugin announcement (Make AI)](https://make.wordpress.org/ai/) - [WordPress Playground: 2025 Year in Review](https://developer.wordpress.org/news/) - [WordPress Coding Standards 3.3.0 changelog](https://github.com/WordPress/WordPress-Coding-Standards/releases) - [Styling accordions in WordPress 6.9](https://developer.wordpress.org/news/) - [Border radius size presets in WordPress 6.9](https://developer.wordpress.org/news/) ## 🗣️ Paraphrase - The article recaps December 2025 updates for WordPress developers, centered on the 6.9 “Gene” release. It highlights new AI experimentation tools, experimental navigation/layout blocks, code‑quality updates, removal of obsolete Flash code, and improvements to data handling, routing, and block design controls. - It also surveys progress in WordPress Playground—from plugin compatibility and performance to browser‑based debugging and PR previews—and links out to the WordPress 6.9 Field Guide and detailed dev notes so developers can explore changes more deeply and start testing for WordPress 7.0. ## 📰 Newsletter WordPress 6.9 “Gene” has landed, and December’s “What’s new for developers?” is packed. You’ll find a brand‑new AI Experiments plugin for safe, pluggable AI prototypes; upgraded experimental Breadcrumbs and Tabs blocks; smarter Data Views/Forms; and a fully Flash‑free core. The HTML, Accordion, Cover, and Math blocks all level up, while the `@wordpress/boot` router and `contentOnly` template lock move the admin redesign forward. Playground also hits 99% plugin compatibility, adds OpCache, Xdebug, WebP/AVIF, Blueprint live editing, and PR preview environments—making browser‑based WordPress dev more realistic than ever. Grab the 6.9 Field Guide and start testing your themes and plugins for the 7.0 cycle. ## ✅ Action Items #### DevRel - Promote the AI Experiments plugin with concrete code samples (e.g., custom AI experiments) and short live demos. - Create workshops on building with experimental Breadcrumbs/Tabs, and on configuring `contentOnly` template locks safely. - Update quickstarts and starter repos to use the new HTML block modal, Button pseudo‑class styling, and Cover video backgrounds. - Run campaigns encouraging developers to test plugins/themes against WordPress 6.9 and the latest Gutenberg, reporting regressions early. - Facilitate community testing sprints focused on Boot routing and Playground PR preview workflows. #### OSPO - Document policies for integrating external AI providers via the AI Client SDK (data handling, logging, and key management). - Include WPCS 3.3.0 in automated scans and update coding‑standards baselines for all WordPress‑related repos. - Ensure Flash removal doesn’t conflict with downstream forks or legacy enterprise setups; define an exception‑handling process if needed. - Track adoption of Playground‑based testing (Blueprints, PR previews) in internal contribution workflows. #### Community - Host contributor sessions around refining experimental Breadcrumbs/Tabs into stable blocks by the 7.0 cycle. - Offer pairing for testing themes/plugins with the new `contentOnly` behavior and Accordion changes. - Share success stories using Playground’s Blueprint gallery and PR preview workflows to lower onboarding friction. #### WordPress - Core: prioritize regressions around Accordion CSS, `contentOnly` insertion rules, and routing integration for plugins. - Core Performance: benchmark OpCache gains and Playground performance patterns to identify optimizations for production sites. - Core AI: treat the AI Experiments plugin as a reference for guardrails, observability, and provider‑agnostic API design. - **Core Program Team:** coordinate cross‑team testing plans for major 7.0 features, especially routing and experimental blocks stabilization. - Mobile: explore surfacing AI‑generated titles and new block features in mobile editors where feasible. - Playground: expand Blueprint templates to cover 6.9 features (Accordion, tabs, AI Experiments) and common testing scenarios. - Community: update meetup/WordCamp materials to include 6.9 highlights and Playground‑based live demos. - Training: publish lessons on using the new block capabilities, Data Views/Forms, and the AI Experiments plugin. - Marketing: run an education‑focused 6.9 campaign that highlights developer tooling (Playground, Boot routing) as well as user‑facing features. - Support: prepare help‑desk scripts and docs covering Flash removal, Accordion quirks, and new Cover/HTML block UIs. - Design: document patterns for tabbed layouts, breadcrumbs, and video backgrounds in the design library. - Documentation: ensure DevHub/HelpHub pages cover 6.9’s new APIs and `theme.json` options (e.g., Button pseudo‑classes, border‑radius presets). - Photos: curate imagery for updated docs and tutorials (Site Editor, new block UIs, Playground screenshots). - TV: encourage short screencasts showing AI Experiments, HTML block modal, and Playground PR previews. - Polyglots: verify that new block controls and Data Views/Forms UIs are localizable; update glossaries as needed. - Accessibility: test new blocks and the HTML modal for screen‑reader, keyboard, and contrast compliance. - Meta: integrate Playground PR previews with core and plugin repos where appropriate; monitor reliability. - CLI: consider commands or scaffolds for Playground Blueprints and AI experiment boilerplate. - Hosting: align default environments with 6.9 requirements (no Flash, PHP 8.x support) and encourage Playground usage for debugging. - Tide: incorporate checks relevant to 6.9 changes where possible (e.g., deprecated Flash references, coding standards). - Openverse: note potential uses of video backgrounds and media formats (WebP/AVIF) across the ecosystem. - Themes: adjust review guidelines for new blocks (Accordion, Tabs, Breadcrumbs) and `contentOnly` templates. - Plugins: audit for Flash dependencies; encourage testing with 6.9/Playground and publishing compatibility notes. #### The WPOCC - Programs: consider microgrants for maintainers improving experimental blocks, testing 6.9 features, or extending Playground tooling. - Projects: sponsor documentation and onboarding sprints around 6.9 and the admin redesign. - Funding experiments: pilot matched grants for plugins adopting AI Experiments responsibly or shipping Playground‑friendly Blueprints. ### FAIR - Promote transparent, provider‑agnostic AI integrations via the AI Experiments plugin and WP AI Client SDK. - Encourage public governance artifacts for AI usage and testing infrastructure (Playground, routing) to prevent capture by any vendor. - Treat new dev‑tools (Playground, Blueprints) as shared infrastructure and document stewardship expectations. ## 🧪 Hypotheses - H1: Providing a first‑party AI Experiments framework will reduce the number of bespoke, insecure AI integrations in plugins. - H2: Experimental Breadcrumbs and Tabs blocks will increase adoption of block‑based navigation/layout patterns in themes. - H3: Removing Flash and improving WPCS will reduce security‑related vulnerabilities and maintenance effort in core and plugins. - H4: Wider use of Playground (Blueprints, PR previews) will shorten feedback loops and increase contribution quality. ### 📊 Methodology - Compare patterns of AI integrations in the plugin directory before vs. after AI Experiments adoption (APIs used, security incidents). - Track usage metrics of Breadcrumbs/Tabs blocks in themes and sites over time (e.g., pattern exports, theme.json usage). - Analyze vulnerability reports and coding‑standards violations pre‑ and post‑6.9/WPCS 3.3.0. - Measure contributor throughput, time‑to‑review, and bug rates on PRs using Playground previews vs. traditional local setups. ### ❓ Questions - How opinionated should core be about AI UX and governance vs. leaving this entirely to plugins? - What stabilization criteria should experimental blocks meet before inclusion in non‑experimental builds? - How can Playground’s near‑universal plugin support be used to automate compatibility testing at scale? - Are there remaining corner cases where Flash removal could break legacy workflows? ### 🔮 Future Research - Patterns and guidelines for AI‑assisted authoring in the block editor that respect user intent, privacy, and accessibility. - Best practices for designing advanced layout/navigation blocks (Tabs, Breadcrumbs) that remain theme‑agnostic. - Expanded Playground capabilities for full‑stack testing (e.g., multi‑site, object cache simulation, perf scenarios). - Further standardization of routing and state management for the redesigned admin. ### 💡 Implications - Practice: developers can standardize AI and routing integrations, lean on Playground for faster review, and simplify front‑end CSS via `theme.json`. - Policy: organizations need AI and dependency policies that recognize new WordPress AI and Playground workflows. - Security: Flash removal and stricter coding standards reduce an entire class of legacy risk. - Education: training material must cover new blocks, patterns, and tooling to keep agencies and freelancers current. - Funding: shared infrastructure like Playground and core AI tooling becomes a strong candidate for strategic investment. ### 🧠 Learning Styles Assessment - Reading level estimate: roughly Flesch–Kincaid grade 10–11 (technical vocabulary but conversational tone). #### 👀 Visual learners - Present: screenshots of Site Editor, blocks, and UI panels. - Improve: add architecture diagrams for Boot routing and Playground pipelines, plus before/after visuals for key blocks. #### 🔊 Aural learners - Present: indirect link to State of the Word (spoken overview). - Improve: provide a 3–5 minute audio summary of “What’s new for developers?” and short screencast narrations. #### 🗣️ Verbal learners - Present: clear descriptions of each feature and rationale. - Improve: add more analogies (e.g., “Playground as a WordPress lab”) and a concise glossary for new terms. #### 🧩 Kinesthetic learners - Present: implied hands‑on actions (enable experiments, test in Playground). - Improve: explicit checklists and step‑by‑step labs (e.g., “Build your first AI experiment”, “Test a plugin in Playground”). #### 🧠 Logical learners - Present: lists of changes and cause‑and‑effect framing (e.g., routing performance, OpCache gains). - Improve: tables comparing pre‑ and post‑6.9 behaviors and decision trees for when to adopt experimental features. #### 🧑‍🤝‍🧑 Social learners - Present: encouragement to collaborate and test together. - Improve: guided discussion prompts for meetups and contributor days, plus structured feedback forms. #### 🧘‍♀️ Solitary learners - Present: the article is readable solo with links to deeper material. - Improve: self‑check questions and short reflection prompts at the end of each section. #### 🌿 Naturalistic learners - Present: no explicit environmental framing. - Improve: tie Playground and performance work to energy efficiency and sustainable hosting practices. ### 📊 Accessibility Assessment #### Screen reader semantics - Present: proper headings and alt‑text‑like descriptions for images. - Improve: ensure all decorative images are marked as such and confirm language attributes on the page. #### Keyboard navigation - Present: standard WordPress.org navigation patterns. - Improve: verify focus states and skip links specifically for this article template. #### Contrast and readability - Present: WordPress.org generally meets contrast guidelines and uses legible fonts. - Improve: check code/UI callouts and captions for contrast at small sizes. #### Text resizing and reflow - Present: responsive layout. - Improve: verify that screenshots and wide tables remain usable at 200% zoom without horizontal scrolling. #### Media and captions - Present: static images; State of the Word video has captions. - Improve: add captions/alt text callouts beneath key screenshots and an optional transcript‑like summary of the article. #### Forms and interactions - Present: minimal interactive UI on the article page. - Improve: ensure any embedded Playground/preview links are clearly labeled and keyboard accessible. #### Standards reference - Map refinements to WCAG 2.2 AA criteria for non‑text contrast, reflow, and keyboard operability. ### 🌍 DEIB Assessment #### Cultural breadth - Present: global WordPress community is implicitly addressed. - Improve: highlight examples from multiple regions/locales and mention i18n benefits (e.g., Intl extension, RTL handling). #### Inclusive language - Present: friendly, gender‑neutral tone. - Improve: define technical jargon more often for non‑expert readers. #### Neurodiversity support - Present: structured sections and bullet lists. - Improve: increase consistency in section formatting and add summary boxes for dense technical sections. #### Representation - Present: generic illustrations and screenshots only. - Improve: include diverse personas and use alt text that respectfully describes people when present. #### Psychological safety - Present: positive, welcoming, and encouraging voice. - Improve: link explicitly to community guidelines and contributor support resources when inviting participation. ### ✅ Logical Validity #### Strong reasoning - The case for removing Flash is strong causal reasoning: unsupported tech → security/perf risk → remove legacy code. - Playground perf claims are supported by a concrete metric (OpCache cutting response times by 42%), a good example of quantitative evidence. #### Fallacies - No major fallacies detected; promotional tone but not misleading, as claims are modest and often linked to official posts. #### Tone of voice - Optimistic, community‑centric, and mildly promotional, balanced with practical notes about testing and upcoming stabilization work. ### 🛡️ DARVO Analysis - Deny: no denial or minimization of problems; known bugs (Accordion) are acknowledged. - Attack: no attacks on critics or users. - Reverse victim/offender: not present; issues are treated as normal parts of development, with fixes scheduled. ## 🎯 Conclusion WordPress 6.9 “Gene” delivers a substantial set of developer‑focused improvements: AI experimentation, richer blocks, modernized core, better routing, and a much more capable Playground. The practical next step is to upgrade your test environments, run your plugins/themes through the latest Gutenberg and Playground, and start experimenting with the new AI and block capabilities while keeping an eye on the 7.0 cycle for stabilization. --- ## 🧱 Refactor Appendix (append after 🎯 Conclusion) ### 📚 Literature Split Pad - Purpose: Stage Konik CEE units that become per-source Literature notes. - Split level: **H3**. - Include verbatim quotes under 25 words and a [view highlight] link. ### [H1] 5–10-word present-tense claim > [!quote] [{Title or entity}]({ARTICLE_URL}) by [[{Author or [MISSING]}]] via [[{Site or [MISSING]}]]. Published {DATE_OR_[MISSING]}. > “Short quote, verbatim, ≤25 words.” Two lines: context and use. Cite data if relevant. [view highlight]({ARTICLE_URL}#H1) #xref #articleseed ID:rw_[MISSING] ### [H2] 5–10-word present-tense claim > [!quote] [{Title or entity}]({ARTICLE_URL}) > “Short quote, verbatim, ≤25 words.” Two lines: context and use. [view highlight]({ARTICLE_URL}#H2) #xref ID:rw_[MISSING] --- ### 🔖 Atomic Split Pad (Zettel Candidates) - Purpose: Promote reusable claims into Atomic notes. - Split level: **H4**. - Each item: one idea, present tense, specific, testable. #### [Z1] 5–10-word present-tense claim - Scope/condition in one line. - Pointer to page/time or dataset. - Links: [[Parent-Concept]] [[Related-Idea]] #### [Z2] 5–10-word present-tense claim - Scope/condition in one line. - Pointer to page/time or dataset. - Links: [[Parent-Concept]] [[Related-Idea]] --- ### ✏️ Fleeting Queue (Extract by Selection) - Purpose: Capture quick actions or sparks for Fleeting notes. - Extraction: **Select one line** → “Refactor: Extract selection to new note (content only).” - Keep each line short and self-contained. - [F1] Short action — context/{ARTICLE_URL} #fleeting #inbox - [F2] Short action — context/{ARTICLE_URL} #fleeting #inbox - [F3] Short action — context/{ARTICLE_URL} #fleeting #inbox ---