Any license code (serial number) is entitled to unlimited "update". For instance, from version 5.0 to 5.2., updates are free. You only need to download it from our website or go to "Help" > "Check for Updates". But if you intend to upgrade (e.g. 5.2 to 6.x), you must pay upgrade fee in ZEON online store (more about "Updates" and "Upgrades").
Note: upgrades are free for subscription users during the subscription period.
See if you are eligible for the upgrade discount program, please refer to https://store.gaaiho.com/buy/upgrade-add-user.aspx