Joomla upgrades require planning, not just version changes
Older Joomla websites often include legacy templates, outdated extensions, custom overrides, or deprecated code paths that cannot simply be pushed into a newer version without review. That is why a real Joomla upgrade is part migration, part compatibility work, and part risk management.
A good upgrade should improve support status, security, and maintainability while protecting the parts of the website that still matter to the business.