Dokany is a third party software. It is not installed automatically anymore since 1.6.
There is a notification at the end of the install process hinting you to dokany or WinFSP.
Its up to you which virtual file system you want to use.
So please check if dokany is installed on your system (I guess not), then choose if you want to use dokany, WinFSP (or even both) and install it. Then the according option is available in cryptomator.
(maybe Cryptomator restart is necessary)