Hextech crafting question
So after searching a lot trough the boards and not finding anything 'official', I would like to ask a question to anyone (including Rioters) regarding hextech crafting.
I own every champion in this game, and after recently opening a champion shard for Nami I was wondering what I could do with it. I looked through websites and boards, and some of them mentioned that I could use the shards to unlock a 6th level of mastery. I haven't found anything official from Riot so I'm asking myself whether this is true or false (or not implemented yet). My question is now: Is this true? And if so, how can I unlock that mastery level?