I have two RB450G’s v5.11 in both cases the IPv6 package is listed in the package list however it is grayed out and I cannot seem to get it enabled. Did I not read that RouterOS supported IPv6? Ah, any help would be greatly appreciated!
In webfig go to system → packages and click on ipv6 (or any other package in the list). This will take you to a page with 3 buttons across the top - [Cancel] [Enable] [Disable]. Click enable. You may need to reboot for it to take effect.