I am using a free license key with Version 6.10. However, upgrading to Version 7.x leads to this key becoming invalid. It seems that it is necessary to upgrade the license key to work with the new version. But I can't find a proper option on the website to do so.
Thus, I would like to know how to do that or if simply a new free key must be generated for the new version to work.
Yes, you are absolutely correct - unfortunately, the free license keys are not upgradable. Therefore, you simply need to generate a new license key using this form.