Joomla!, VirtueMart, OSCommerce, and Zen Cart all release updates periodically.

All minor updates will be applied to the customers' account for free. The timeframe for updates will depend on the nature of the update (security or feature enhancement).

Major Updates (like Joomla! 1.0->1.5) typically are harder to install and also contain significant changes in user interfaces and features. Major updates can be applied for $50 with the customer's consent.