Mormons: Is the LDS cannon closed?

I have seen the president of your church in the past making church changing "revelations" (Giving blacks the priesthood, Change the temple ceremony). Not one of these "important" changes are added to your cannon. But a statement of someone named Oliver Granger being held in fond remembrance is included.. Who was this guy, can you honestly say that you, or the church as a whole for that matter remembers him at all let alone fondly.. Is that more important to the church than the more recent changes, unless of course your cannon is indeed closed. If it is then you don't need a prophet...