Plugin Update Mechanism — a practical guide to WordPress plugin updates with clear examples you can reuse in real projects.
WordPress Plugin Development Series (85/95). Prefer one article? Read the complete WordPress plugin development tutorial.
Short description
WordPress.org handles updates for hosted plugins. Premium plugins use custom update APIs via transient filters.
Update sources
wordpress.org SVN hosting
or
custom updater (EDD, Freemius, self-hosted API)