While our one-time purchase licenses work indefinitely and never run out, older versions are discontinued after some time and if a specific version or service stops working, we would not be able to provide a fix, because the version is no longer in development.
Since we believe that finding out after the purchase that we cannot help would not be fair, we instead encourage you to upgrade to the newest version, where we can implement any needed fixes. An upgrade purchase automatically includes 1 year of support.
Free licenses and Personal and Business license subscriptions are always valid for the current major version.