600 sites 8 years outdated: A massive multisite WordPress upgrade, Jesse Dyck
Summary
Jesse Dyck from Evolving Web presented a comprehensive case study of upgrading a massive WordPress multisite network that had been frozen since 2017. The project involved nearly 700 subsites, 200 plugins, and 43 themes with a half-gigabyte compressed database and 143 gigabytes of files. The network was running WordPress 4.
9 and faced a mandatory upgrade to PHP 8. Dyck outlined a systematic six-phase approach: setup and auditing, cleanup, testing plans, upgrade execution, deployment, and post-upgrade maintenance. The audit phase was emphasized as the most critical, involving extensive inventorying of all sites, plugins, and themes to assess their status, compatibility, and maintenance requirements.
The team created comprehensive spreadsheets documenting every component and triaged items for removal, upgrade, replacement, consolidation, or patching. After cleanup, they reduced the network to approximately 350 sites, significantly fewer plugins and themes, and cut database and file sizes in half. Key tools included WP-CLI for data extraction and automation, PHPCS for code compatibility checking, and Playwright for visual regression testing with before-and-after screenshots.
The team also utilized AI tools like ChatGPT to generate WP-CLI commands and automated much of the auditing process. Launch coordination involved careful planning of communication channels, user acceptance testing, maintenance mode implementation, and detailed checklists. Common issues encountered included style changes due to plugin updates, PHP compatibility problems with legacy code, and the need to maintain classic editor functionality for users transitioning from pre-block editor WordPress.
The project successfully modernized a complex, legacy multisite installation while maintaining functionality across hundreds of sites.
Key Takeaways
- •Comprehensive auditing is the most critical phase of large-scale WordPress upgrades - invest heavily in cataloging all sites, plugins, and themes before proceeding
- •Cleanup before upgrade can reduce database and file sizes by 50% or more, dramatically improving deployment and rollback times
- •WP-CLI combined with AI tools like ChatGPT can automate complex data extraction tasks that would otherwise take days of manual work
- •Visual regression testing with tools like Playwright is essential for detecting subtle CSS and markup changes across hundreds of sites
- •PHPCS can identify PHP compatibility issues in legacy plugins before upgrade, allowing for proactive patching or replacement
- •Maintenance mode implementation should disable admin logins except for super admins during lengthy upgrade deployments
- •Classic editor and classic widgets plugins should be network-activated when jumping from pre-block editor WordPress versions
- •Distributed user acceptance testing involving actual site administrators is more effective than centralized testing alone
- •Detailed checklists and progress tracking become critical for projects spanning months with hundreds of components
- •Some legacy themes may be too complex to upgrade - consider migrating those sites to alternative platforms
- •Object caching should be prioritized post-upgrade once plugin compatibility issues are resolved
- •Performance gains from WordPress version upgrades may not be immediately noticeable on small sites but stability improvements are significant
Transcript
All right. So, yeah, this is me. Um, I'm Jesse. I'm the I lead our WordPress team and I am a solutions architect at Evolving Web doing all things WordPress. Um, I've been a WordPress user since actually looked up the other day. I found an old version of a previous website from 2007. Um, so that was my my first WordPress experience, I believe. Um, >> might as well. >> Oh, there you go. Um but uh today I want to talk about a recent project that we did um we were working on. We inherited a WordPres...
