The bazaar in my kingdom has been stuck on Tier X for at least the last two cycles. The actual tier, requirements and rewards have been correct, but this has caused confusion with fellow kingdom members before.
I believe tier X is the highest tier for what is available to purchase.
The rewards tier is what goes up higher.
@Intelligent is correct, Bazaar Tier max is X - but have passed on feedback that Purchase Reward Tiers and Bazaar Tiers are two different things but read confusingly.
So, we will look at reviewing/changing this to avoid further confusion!