Key Takeaway:
Yes, you can safely upgrade WordPress 5.5 to the current version if you follow safe practices and fully test beforehand. Create a full backup, test on staging first, and expect significant security and performance improvements from 4+ years of WordPress development.
If you’re still running WordPress 5.5, you’re missing out on 4+ years of significant security updates, performance improvements, and modern features. More importantly, you’re leaving your website vulnerable to known security threats that have been patched in newer versions.
WordPress 5.5 was released in August 2020. Since then, WordPress has released many updates, including major versions 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, and 6.4 (and incremental patches between them). Each version brings security fixes, bug patches, and new capabilities your site can benefit from.
This guide walks you through everything you need to know to migrate safely from WordPress 5.5 to the current version without losing data or introducing downtime, while preparing for potential compatibility issues.
Why You Should Upgrade from WordPress 5.5
Security Vulnerabilities
WordPress 5.5 has multiple known vulnerabilities, such as cross-site scripting (XSS), directory traversal, file upload bypass, and more. For example, a remote code execution (RCE) vulnerability was patched in WordPress 6.4.3 (CVE-2024-31210), affecting earlier versions. Delaying the upgrade exposes your site to exploits that target those known flaws.
Missing Critical Features & Updates
Since 5.5, WordPress has added features like full-site editing, block-based widgets, global styles, improved site health tools, and more. Running 5.5 means you cannot take advantage of these newer capabilities.
PHP Compatibility & Performance
Older WordPress versions may be less compatible with newer PHP versions, which most hosts now run (PHP 8.x+). While 5.5 may still work, newer versions are better optimized for modern PHP, handle memory more efficiently, and offer faster page loads. However, it’s important to test on your specific hosting environment, since plugin/theme compatibility can also cause PHP errors after an upgrade.
Plugin & Theme Support
Many plugin and theme developers drop support for ancient WordPress versions. You may find updates that require newer core versions, or you might lose access to security patches for specific plugins if you never upgrade the core.
Pre-Migration Checklist
Before attempting an upgrade, ensure the following:
Backup Everything
- Full file backup (via FTP, hosting control panel, or backup plugin)
- Database export (e.g. via phpMyAdmin or hosting tools)
- Test restoring those backups to confirm they work
- Store backups offsite (local, cloud storage, etc.)
Document Your Setup
- Exact WordPress version (5.5.x)
- List of active plugins + their current versions
- Theme name + version
- Any custom code (child theme CSS, functions.php, custom plugins)
- PHP version used by your host
Prepare Your Environment
- Choose a maintenance window (when traffic is low)
- Notify stakeholders/users of potential downtime
- Create a staging environment and clone your live site for testing
- Double-check host support and contact info
What You Stand to Gain
Upgrading from WordPress 5.5 can bring:
Security Enhancements
- Patches for known vulnerabilities (XSS, RCE, traversal, etc.)
- Stronger default security headers and hardening
- Better site health monitoring & alerts
- Support for automatic (background) updates of core for minor/security releases
Performance Improvements
- Better integration with modern PHP versions
- Improvements in block editor performance, rendering, and caching compatibility
- Lazy loading and image optimizations (e.g. WebP support)
- More efficient database queries and memory usage
For comprehensive guidance on optimizing your site’s speed after migration, check out our guide on WordPress site performance optimization.
Modern Editor & Design Features
- Full Site Editing (FSE) and block templates
- Global styles, block patterns, and design tools
- Block-based widgets/widget editor
- Template editing via admin interface
Better Admin Experience
- More intuitive admin UI, smoother interaction
- Enhanced site health tools that detect configuration issues
- Accessibility updates and usability improvements
Step-by-Step Migration Methods
Choose based on technical ability and site complexity:
Method 1: Automatic Update (Easiest)
Best for simple sites with compatible plugins/themes
- Go to Dashboard → Updates
- WordPress will show available core updates
- Click “Update Now”
- Wait while it updates (do not close browser)
- Clear caching (server, plugin, browser)
- Immediately test the front-end and back-end
⚠️ Caution: Jumping many major versions at once can cause compatibility issues. Always test first.
Method 2: Staged / Incremental Update (Recommended)
- Clone live site to staging (files + database)
- On staging, perform the upgrade (automatic or manual)
- Test all plugin/theme functionality, fix errors
- Document any needed changes or patches
- When confident, repeat the process on the live site
- Monitor the live site for 24–48 hours post-upgrade
Method 3: Manual FTP / File-Based Update
Best for sites with custom changes or restrictions
- Download the latest WordPress ZIP from wordpress.org
- Extract locally
- Do not overwrite the wp-content directory or the wp-config.php
- Upload (via FTP / SFTP) all core files and directories, replacing existing ones
- Visit yoursite.com/wp-admin → WordPress will prompt to update the database
- Run the upgrade and verify all site functionality
- Reactivate any disabled plugins/themes and test thoroughly
Common Problems & How to Fix Them
| Problem | Symptoms | Solutions |
|---|---|---|
| Plugin incompatibilities | Errors, broken pages, missing functionality | Deactivate suspect plugins, seek updated versions or replacements |
| Theme layout broken | CSS missing, misaligned sections | Temporarily switch to the default theme, fix the custom theme for the new version |
| Database errors / white screen | “Error establishing DB”, blank pages | Restore backup, check wp-config.php, re-run database upgrade |
| Performance slow post-upgrade | Long load times, slow queries | Clear all caches, optimize DB, check for plugin conflicts |
| Login/admin inaccessible | Can’t access the dashboard | Use recovery mode, check error logs, and fallback to backup |
| Missing content or broken permalinks | 404 errors, missing posts | Reset permalinks (Settings > Permalinks), regenerate .htaccess |
For emergencies, restore backup immediately and diagnose on staging.
Post-Upgrade Best Practices & Maintenance
- Enable auto-updates for minor/security core releases (if safe)
- Enable auto-updates selectively for trusted plugins/themes
- Monitor Site Health (but be aware it may flag disabled auto-updates)
- Use caching, image optimization, and performance plugins
- Harden your site: enforce HTTPS, disable file editing, set secure file perms
- Regularly back up and test restores
- Run security scans and audits periodically
Professional Migration Assistance
Complex websites often benefit from professional migration help, especially if you have:
- Custom-coded plugins or themes that may need compatibility updates
- E-commerce functionality where downtime costs money
- Multiple sites that need coordinating updates
- Limited technical experience with WordPress administration
- Previous bad experiences with WordPress updates
A qualified WordPress security expert ensures zero-downtime updates, complete testing, and immediate issue resolution if problems arise.
FAQ
Will upgrading WordPress 5.5 break my website?
Not if you follow proper procedures. First, create a full backup, test on staging if possible, and be prepared to restore from backup if needed. Most sites upgrade smoothly, but preparation prevents major problems.
How long does WordPress migration take?
Simple sites update in 5-10 minutes. Complex sites with many plugins might take 30-60 minutes. Professional migration services can complete complex sites in 1-2 hours with zero downtime.
Can I revert if something goes wrong?
Yes, if you have a complete backup, you can restore your files and database to their exact state before the upgrade. This is why backing up is absolutely critical before starting.
Should I update plugins and themes at the same time?
Update the WordPress core first, then test everything. After confirming that the WordPress upgrade was successful, update plugins and themes one at a time. This makes troubleshooting easier if problems occur.
Do I need professional help for WordPress migration?
Following this guide can upgrade most simple sites. Consider professional help if you have custom code or e-commerce functionality or if your business can’t afford any downtime during the update process.
Key Takeaways
- WordPress 5.5 has known security vulnerabilities – Upgrade to protect your website from exploits.
- Proper preparation prevents problems – Always backup completely and test on staging first.
- Staging environments save time – Test updates on staging to avoid surprises on your live site.
- Professional help is available – Complex sites benefit from expert migration assistance.
- Benefits outweigh risks – Modern WordPress versions are more secure and capable than 5.5
Ready to upgrade your WordPress 5.5 site safely? Our WordPress migration specialists handle complex upgrades with zero downtime and complete testing. Get a free migration consultation to discuss your specific needs and timeline.