You are welcome to evaluate the program for a certain period of time mentioned in the program without paying. If you would like to continue to use the program after this evaluation period, you have to purchase a license key. Extended usage requires the product to be licensed. We encourage you to license the Software and support its further development. To license the program, please go to the Viper FTP website to purchase a license key at: http://viperftp.com
Viper FTP License Key
By registering and completing the payment process you obtain a license key for the Software.
Upon receipt of payment, the user is granted a non-exclusive license to use Viper FTP on as many computers as defined by the licensing terms according to the number of licenses purchased, for any legal purpose.
Distribution of the licensed version is not allowed. You are not allowed to distribute any kind of registration codes, license keys or algorithm to build them.
You may make copies of the Software only for backup and archival purposes.
Viper FTP User Guide