GS-201 Mark II isn't accepting my license.
If you own a license of GS-201 version 1 and you're trying to use that for activating GS-201 Mark II, that won't work.
GS-201 Mark II is a new product and requires a new license. However, as an owner of version 1 you deserve a discount, and in the end you pay less than the price of version 2 for owning both versions.
Please have a look at the product page for learning more about the new features and the improvements over version 1, and also feel free to download the free demo and test it by yourself.