What’s New in WordPress Development: September 2025

Whether managing a business site or maintaining clients’ WordPress installations, staying updated on platform advancements is key to ensuring fast, secure, and competitive websites. Here are the essential updates and tips from the latest WordPress developer news:

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New Features

Abilities API Composer Package

A new Composer package (wordpress/abilities-api) is now available for early experimentation. This API aims to extend how plugins interact with WordPress by defining “abilities” your site and plugins can tap into. Expect easier integrations and more standardized capabilities when WordPress 6.9 is released[1].

Accordion Blocks in Core

WordPress introduces core Accordion blocks: Accordion, Accordion Item, Accordion Header, and Accordion Panel. They’re built for full accessibility (WCAG, USWDS standards) and powered by the Interactivity API, making them robust and easy to style. Enable via Gutenberg > Experiments for client FAQs, product details, or collapsible sections—all with simple drag-and-drop setup[1].

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Maintenance & Styling Tips

Styling Form Inputs in theme.json

WordPress now gives maintainers granular control over input element styling through theme.json. Want all input fields with a custom border and color? Add configurations like:

"elements": {
  "textInput": {
    "border": {
      "radius": "0",
      "style": "solid",
      "width": "1px",
      "color": "red"
    },
    "color": { "text": "var(--wp--preset--color--theme-2)" }
  }
}

Try these adjustments by activating the Form block in Gutenberg experiments and directly customizing clients’ or your own theme. Maintenance teams can now guarantee consistent branding and accessibility for all forms[1].

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Plugin and Tools Highlights

• Data Views: Infinite scroll, card layouts, and more table configuration options.
• Create Block Package: Now supports clean, variant-specific template files—simplifies custom block creation for agencies and maintainers.
• Async Validation: Form components now support async validation, boosting reliability for custom portals and client dashboards.
• useServerSideRender Hook: Adds new options for dynamic content rendering—great for performance-tuned and SEO-focused sites[1].

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AI & Developer Resources

• The Core AI team released v0.1.1 of the Abilities API and PHP AI Client v0.1.0, with live chatbot demos proving new extensibility.
• MCP adapter now supports Cursor; client-side testing volunteers are encouraged for early access.

Developers and maintainers can look forward to easier prototyping and AI-powered automation—critical for rapid troubleshooting and site enhancement[1].

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Playground and CLI

• Playground Query API now allows multiple theme/plugin installs in one go.
• New CLI flags let users set custom local environment URLs and auto-mount project folders—ideal for maintenance agencies managing multiple staging environments.
• PHP WASM and browser-based prototyping tools mean less friction when debugging or demoing code on live sites[1].

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Theme Improvements

• Date block now supports custom dates and binds directly to post metadata.
• Query Loop block supports displaying post type labels—useful for archive and maintenance listing templates.
• Early exploration into template duplication and active template management—theme authors should prepare for simpler A/B testing and faster deployment cycles.
• theme.json now supports border radius presets—easily maintain brand consistency across client sites.
• Bug fixes for post excerpts, fieldset styles, CSS variables, and Cover Block placeholder handling will save time for maintainers and prevent minor visuals creeping into production[1].

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Editor Picks & Resources

Read in-depth guides:

• Registering custom social media icons for WordPress 6.9
• Namespaces and coding standards for plugin development (maximize readability and scalability)
• Refactoring multi-block plugins for smarter, cleaner architecture

If maintenance is your focus, these guides offer actionable examples for optimizing code quality and future-proofing custom work[1].

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Stay tuned for more updates from wpmaintainly.com—your partner in keeping WordPress sites performing at their best.

Citations :
[1] What’s new for developers? (September 2025) https://developer.wordpress.org/news/2025/09/whats-new-for-developers-september-2025/