The license works for one major version and the updates to that version (for example version 8.0, 8.1, 8.2 but not 9.0). When a new major version is released you will not be forced to upgrade, but you will not have access to the new functionality from the new release. You can expect a major version approximately every year.
You can securely pay with your Visa, Mastercard, American Express, Discover, Banking Account or Paypal.
No, you can use the license for only for 1 computer. Discounts are available if you purchase more versions at the same time.
FLV Downloader only works on a PC.