To register WinRAR 6.11 or any other version, you must purchase a license from the Official WinRAR Store. WinRAR licenses are and valid for all future updates. How to Register WinRAR
6.11 continues to support the improved RAR5 format, which offers better compression ratios, faster recovery, and better handling of damaged archives. Improved Recovery: winrar 6.11 key
In fact, the developers have stated that this nag screen is an intentional "honor system." They rely on businesses and loyal users to pay, while home users can continue using the software for free indefinitely. To register WinRAR 6