Seven things to check before a WordPress major upgrade — before "patch what breaks after" becomes a disaster

WordPress major version upgrades (5.x → 6.x, and eventually 6.x → 7.x) are a different animal from minor releases. Minor releases (like 6.4.1 → 6.4.2) are mostly bug fixes with low compatibility risk. Majors land API deprecations, raised PHP minimum requirements, and core block replacements all at once — and those things hit operations hard. The " just hit Update in the admin and patch whatever breaks " workflow can survive on a single personal site, but it tends to fall apart under multi-site maintenance — simultaneous failures across sites overwhelm root-cause triage. This post collects the things worth verifying before you run a major upgrade, as a seven-item checklist . 1. Has the minimum PHP version been raised? Major WordPress releases sometimes raise the minimum supported PHP version (6.6 lifted it to PHP 7.2.24, and a future 7.0 will very likely require PHP 8.x). What matters operationally isn't just the server's PHP version and WordPress's stated minimum — it's the intersection with the PHP versions your plugins and themes actually run on . You can usually upgrade your server's PHP, but older themes and plugins not running on new PHP isn't rare. A subtle failure mode here: traps like PHP 8.2+ deprecated warnings leaking into older WP-CLI JSON output , where nothing visibly errors but your operational tooling silently breaks. Before upgrading, run wp plugin list --format=json on the production PHP environment and verify you're getting clean JSON. That one check catches a lot of post-upgrade pain. 2. Audit "Tested up to" for every plugin Each plugin's readme.txt carries a Tested up to: X.X line — the developer's declaration of the highest WordPress version they've actually tested against . It's the first signal for major-upgrade compatibility audits. WP-CLI gives you the inventory in one shot: wp plugin list --fields = name,version,update_version,update --format = table Plugins where "Tested up to" is old AND no updates in the last year deserve scrutiny. Acti