All users of our software are entitled to get free minor upgrades. For example upgrades from version 1.0 to version 1.1 etc are free.
These upgrades are not limited in time as long as new major version is not released.

We will charge a small upgrade fee for only the major software release.
For example when new software version will include significant changes or new features.
In that case the number of software version will be changed from 1.0 to 2.0

Even though we are releasing major version every few year, not always major version upgrade is paid version. And that's good news.

We reserve right to change the policy without further notice.