One reason why the move was delayed for so long is the sui-generis database rights contained in 4.0. See Jimmy Wales answer here: https://www.youtube.com/watc

One reason why the move was delayed for so long is the sui-generis database rights contained in 4.0. See Jimmy Wales answer here: https://www.youtube.com/watch?v=Zpof5J6jjZ4&t=3738s https://www.youtube.com/watch?v=Zpof5J6jjZ4&t=3738s The solution adopted was to include a waiver in the Wikimedia Terms of Use: Where you own Sui Generis Database Rights covered by CC BY-SA 4.0, you waive these rights. As an example, this means facts you contribute to the projects may be reused freely without attribution. https://foundation.wikimedia.org/wiki/Policy:Terms_of_Use https://foundation.wikimedia.org/wiki/Policy:Terms_of_Use