WordPress Core Updates: Compatibility vs Popular Plugins

WordPress core updates are essential for keeping our beloved CMS secure and relevant, but they also pose risks to site stability when not managed carefully. As WordPress core contributors, DevriX is part of the rigorous test updates, but we can’t control how, when or if at all, plugin developers respond.

WordPress has core releases categorized into major and minor, with minor updates being auto-installed by default. However, many site owners disable auto-updates out of fear – a mistake leading to vulnerabilities. The 2023 security advisory by Wordfence noted that 90%+ of exploited WP sites were running outdated core or plugin code.

WooCommerce had known issues during the 6.2 to 6.3 transition period, affecting checkout logic and stock syncing.

The bottom line? Avoiding updates is riskier than updating – if done right. Staging site, proper backups, and plugin conflict testing are a must.

What is a core update, really?

Before we get into compatibility, let’s set the record straight on what WordPress core updates actually include. These aren’t just random tweaks under the hood – they’re structured, categorized, and (mostly) predictable.

WordPress core updates fall in two primary buckets, minor and major, and the difference is key to managing risk.

Minor vs. Major Updates

Minor updates are usually safe and automatic. You’ll see versions like 6.5.2 or 6.5.3. These don’t add new features – they fix bugs, patch security issues, and fine-tune performance.

Unless you’ve specifically disabled auto-updates, WordPress will handle these silently in the background. They’re designed to be backward-compatible and rarely cause plugin issues.

Major updates, on the other hand, are a different beast. These are the version jumps you notice – like 6.5 to 6.6. They often introduce new features, API changes, and significant Gutenberg enhancements.

Our core team follows meticulous backward compatibility principles, but major releases inherently still carry a risk – especially for plugins that hook deep into the editor, admin screens, or REST API.

Security Updates

Over 60% of CMS websites use WordPress, making it a massive target for malicious actions. Security updates fix vulnerabilities – anything from XSS attacks to privilege escalation bugs. Security updates are mission-critical, and plugin developers are expected to respond quickly. But if they don’t, you may notice compatibility issues in surprising ways (e.g., login issues, broken nonce validation, etc.).

Maintenance Updates

These are your bug fixes, typo corrections, and cleanup tasks. They can resolve nagging issues like layout quirks in the admin panel, edge case bugs in core functions, or PHP notices on specific server setups. Though usually low-risk, maintenance updates may still affect plugins that rely on tightly-coupled UI behaviors or deprecated hooks.

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Feature Updates

This is where the real tension lies. New features – especially with updates affecting the block editor, media handling, or user roles – can be revolutionary for users but destabilizing for plugins. A new scheduling system, a change to how scripts are enqueued, or even a UX redesign in the admin area can force plugin developers to refactor their codebase fast.

Gutenberg/Editor Updates

If you use the default block editor (Gutenberg), every major update brings new blocks, layout tools, and UI changes. For plugin authors who extend Gutenberg (custom blocks, block controls, editor panels), this can be a minefield. Even a slight refactor in the way attributes are passed can trigger frontend or backend display issues.

REST API Changes

Many plugins and themes now rely heavily on the WordPress REST API for dynamic content loading, headless setups, or AJAX-powered features. Core updates sometimes modify or expand this API, and while changes are documented, not all plugins adapt on time. Lags create broken endpoints, authentication problems, or missing data on the frontend.

In short, a WordPress core update is actually a bundle of updates – each with the potential to affect a different layer of your site.

Why do core updates break your site?

WordPress is known for its dedication to backward compatibility – often going to great lengths to avoid breaking existing functionality. But despite that effort, updates can still cause serious issues, particularly when plugins are involved.

Why? Short answer: because plugins live in their own world, and not all of them play by the same rules – or update at the same pace.

Let’s look at the core reasons core updates break sites.

Plugin Dependencies on Deprecated Functions

When WordPress deprecates a function, it doesn’t immediately remove it. Instead, it’s flagged internally and is replaced with a newer, safer, more performant alternative. Good plugin developers watch these deprecation notices and adjust accordingly. Others… don’t.

The result? When a core update eventually removes the deprecated function (or changes its behavior), any plugin still relying on it may throw fatal errors or break silently.

For example, the shift from wp_schedule_single_event() to better event handling in cron caused scheduling plugins to misfire until they updated their codebase.

PHP Version Conflicts

WordPress core updates often increase compatibility with newer PHP versions (e.g., PHP 8.0, 8.1, or 8.2). This is great for performance and security – but only if your plugins are on the same page.

If your plugin uses outdated PHP syntax or doesn’t support stricter type enforcement, prepare for trigger warnings, errors, or blank screens after a core update – even if the plugin worked fine before.

Incompatible JavaScript and CSS

WordPress updates increasingly rely on JavaScript-heavy features, especially in the block editor. A core update might change how a script is loaded, how dependencies are handled, or how block styles are enqueued.

If your plugin:

• Injects scripts into the editor,
• Extends existing Gutenberg blocks, or
• Adds custom block controls,

…then even a small editor API change could lead to broken styling, console errors, or UI elements simply disappearing.

REST API Adjustments

REST API changes can seem small but have wide-reaching effects. A renamed field, an updated response schema, or an altered authentication method could break a plugin’s AJAX calls, front-end rendering, or admin dashboard interactions.

Plugins relying on such endpoints – especially for headless WordPress setups or custom dashboards – can silently fail unless thoroughly tested against new core versions.

Plugin Load Order and Conflicts

Not all plugin issues are caused by the update itself. Sometimes, it’s about how plugins interact with each other in a post-update environment. A plugin that loads before another may now call a function too early. A core update may change when certain hooks are fired, and the load order suddenly matters more.

It’s especially problematic when you’re using complex plugins:

• WooCommerce
• Elementor
• WPML or Polylang
• Advanced Custom Fields (ACF)
• Caching or security suites (like WP Rocket or Wordfence)

Each of these hooks deeply into WordPress internals, and each update is a potential point of failure.

The Plugin Problem: Why Popular Doesn’t Mean Compatible

When most people think about plugin compatibility issues, they assume it’s mainly obscure or poorly maintained ones that cause problems. But in reality, the most popular and actively developed plugins are also the most vulnerable when core updates roll out.

Why? Because popularity brings complexity – and complexity increases the chance of something going sideways.

Larger Codebases = More Points of Failure

Popular plugins (think WooCommerce, Elementor, Yoast SEO) have thousands of lines of code, dozens of contributors, and a range of dependencies – circumstances that makes them powerful, but also fragile in the face of change.

A core update might only tweak a small function in the admin dashboard or modify a Gutenberg API, but that single tweak could impact:

• Editor UI extensions
• Custom REST endpoints
• Schema output
• Metabox rendering
• Customizer integrations

It’s not that these plugins are “badly built”. It’s that the sheer size of their codebase makes full regression testing a heavy lift.

Timelines Rarely Align

The WordPress core team usually announces release candidates and beta versions weeks in advance. But plugin teams have their own schedules and backlogs. Unless a plugin developer is actively tracking and testing against upcoming versions of WordPress, it’s likely they won’t spot compatibility issues until after a release is live, meaning there’s often a lag – sometimes days, sometimes weeks.

Example: Elementor 3.15 introduced layout rendering issues when used with early versions of WordPress 6.3. A fix came relatively quickly, but only after users had already run into broken designs.

Delayed Support for Gutenberg and Full Site Editing

Full Site Editing has been among the most significant shifts in WordPress architecture, but not all plugin authors have embraced it at the same pace. Many still depend on legacy metaboxes, classic editor hooks, or custom shortcodes – all of which are more fragile in an FSE-first environment.

Multilingual and Caching Plugins

Plugins like WPML, Polylang, WP Rocket, or W3 Total Cache often rewrite core WordPress behavior. They intercept queries, modify URLs, buffer output, or override content rendering.

When the core changes how queries are built, how REST API endpoints behave, or how template parts are loaded in block themes, these plugins are first in line to break – sometimes in subtle ways that only emerge over time.

Backward Compatibility

Ironically, the WordPress commitment to backward compatibility can make some plugin developers complacent. There’s an assumption that everything will “just keep working” – until it doesn’t.

Regardless, the plugin market is competitive, and developers prioritize shipping new features over hardening compatibility with beta core releases. The result? Stability often takes a back seat to velocity.

So, what’s the takeaway here?

Don’t confuse popularity with immunity. The most installed plugin on your site might also be the one most likely to crash when the next core update hits – simply because it has more moving parts and more surface area for things to go wrong.

Best Practices on WordPress Core Updates

By now, it’s clear that WordPress core updates are necessary, but also risky if not approached with care. So how do you protect your site without falling behind on updates? It’s all about process and preparation.

Let’s walk through key strategies every WordPress site owner/developer should adopt to minimize compatibility issues.

Use a Staging Environment. Always

If your website brings in revenue, generates leads, or supports a community, it’s too important to update live. Period.

A staging environment is a copy of your live site that lives on a separate subdomain or server. The sole purpose of a staging site is to test updates, plugin behavior, and site functionality before anything reaches your visitors.

Backups Are Not Optional

Before updating anything (WordPress core, plugins, themes) take a full backup. Ideally, this includes:

• The database
• All media uploads
• wp-content folder (themes, plugins, etc.)
• Configuration files like wp-config.php and .htaccess

Turn Off Auto-Updates Strategically

By default, WordPress applies minor core updates automatically. That’s generally safe and good for security. But for major core updates, it’s better to disable auto-updates and apply them manually – on your terms, after proper testing.

How to control core updates:

Via wp-config.php:

define( ‘WP_AUTO_UPDATE_CORE’, false );

Important: Don’t disable updates entirely unless you have a process in place to handle them manually. Delaying updates indefinitely introduces security vulnerabilities.

Maintain a Plugin Update Protocol

Plugin updates shouldn’t be a free-for-all. Create a repeatable process:

• Update in a staging environment first.
• Test critical functionality (checkout, forms, user registration, etc.).
• Update one plugin at a time, especially when using WooCommerce or Elementor.
• Monitor site logs for any new errors or warnings.

A staged rollout will help you identify the exact plugin or update that causes issues.

Monitor Changelogs and Dev Notes

Stay proactive by reviewing:

• WordPress Core Field Guide
• Plugin changelogs (in the WordPress.org plugin repository or GitHub)
• Beta and RC (Release Candidate) notes for upcoming versions

If a plugin you use hasn’t been updated or tested with the latest WordPress version, think twice before making a core update. In some cases, it’s better to wait a few days (even weeks) until plugin authors release a compatible version.

Should You Disable Core Updates? (Hint: No)

Disabling core updates might seem like the safest option – especially if you’ve dealt with plugin breakages, theme glitches, or site downtime after a major release. But while freezing your WordPress version might protect you in the short term, it’s a long-term liability that can cost you in more ways than one.

Let’s unpack the risks and why staying updated (strategically) is the smarter move.

Security Doesn’t Wait

The number one reason to keep WordPress core updated is security. Every update – especially minor ones – includes patches for known vulnerabilities. If your site runs on an outdated version of WordPress, you’re:

• Exposed to known exploits.
• A potential target for automated bot attacks.
• Risking the integrity of your users’ data.

Outdated Core = Plugin Incompatibility

Ironically, the longer you delay a core update, the more (not less) likely your plugins will break.

That’s because plugin developers build against the latest stable version of WordPress. If you stay behind (say, on WordPress 6.2 while the ecosystem moves to 6.5+), newer versions of plugins might:

• Drop support for your outdated core version.
• Introduce bugs you can’t resolve without upgrading.
• Lock you out of useful features.

Suddenly, you’re boxed in: you can’t update the plugins without updating core, but updating core now feels even riskier.

Performance & UX Improvements

WordPress core updates don’t just fix bugs – they also:

• Improve performance (e.g., lazy loading, script handling).
• Enhance editor UX (especially for block users).
• Modernize accessibility and responsive behavior.
  

By avoiding updates, you’re choosing a slower, less user-friendly site. And over time, that can hurt your SEO, engagement, and conversions.

Disabling Updates Isn’t the Same as “Playing It Safe”

There’s a difference between strategically delaying updates and shutting them off completely.

It’s OK to:

• Wait a week or two after a major release.
• Test updates in staging first.
• Follow plugin authors for compatibility notes.

It’s not OK to:

• Turn off updates and forget about them.
• Skip security releases indefinitely.
• Let years go by without touching the core.

If you do that, your site is a ticking time bomb – one core exploit or plugin misfire away from a full crash.

There Are Smarter Alternatives

If you truly need to delay updates, do it smartly:

• Use DevriX to refine, fine-tune and execute ongoing maintenance to fine-tune your update policy.
• Set up notifications for new releases rather than auto-applying them.
• Implement version pinning in your staging pipeline so updates are gated until you manually approve them.

These are all safer than flipping a switch and walking away.

Bottom line? Disabling core updates is a defensive move that creates bigger risks down the line. If stability is your concern, build systems around testing, staging, and update controls – not avoidance.

WordPress core updates aren’t going anywhere. If anything, they’re arriving faster, packing more features, and reshaping how we build and manage websites. That’s a good thing – but only if you’re ready for it.

Staying updated is no longer optional. It’s a core part of your site’s performance, security, and long-term viability. But that doesn’t mean you have to update recklessly. The key is to shift your mindset from reaction to preparation.

Let’s recap the essentials:

• Understand what types of updates are being released – and what they affect.
• Accept that even popular plugins can (and do) break, especially around major releases.
  Create a workflow that includes staging environments, backups, changelog reviews, and manual testing.
• Don’t disable updates unless you’re prepared to handle them manually, and never indefinitely.
• Use the tools and infrastructure available – plugin management dashboards, version control, automated backups, and notification systems – to your advantage.
  

The truth is, most WordPress update disasters don’t come from the updates themselves – they come from a lack of process. If you build a reliable, repeatable update strategy, your site will not only stay stable… it will thrive.

So the next time you see that “An update is available” notice in your dashboard, don’t panic. Just make sure your process is ready – and press update with confidence.