Why most WordPress plugins break on update

A plugin rarely breaks because WordPress changed. It breaks because the plugin quietly depended on something WordPress never promised to keep.

Lean on hooks, not on internals

Actions and filters are the public contract. Reaching into core globals or copying a template function's output ties your code to details that can change in any release.

Version what you store

Every option, table and post-meta key should carry a schema version. When an update runs, compare the stored version to the code's version and migrate on plugins_loaded — not on activation, which only runs once.

Test against the next release

Run your suite against the WordPress beta every cycle. Most breakages are announced in the field guide weeks before they ship.

Boring plugins survive. Clever ones get rewritten.