Predictably, the MP-63 will be replaced by the MP-64, and the JPX-800 and JPX-800 Pro have been upgraded to the new JPX-825 and JPX-825 Pro irons. Less predictably...hell...I'll say shocking is that Mizuno is NOT announcing a replacement for the MP-53. So as of right now...at least to the best of my knowledge, there isn't an MP-54.
Here's the bigger surprise. A few weeks ago we showed a pic of the MP-H4. We basically billed the H4 as a long iron replacement (the new Fli-Hi if you will). The H4, which is more iron than hybrid, I suppose, would fall into the same category as Adams's Transitional Hybrids (again - long iron replacements that are more iron than hybrid/wood). The surprise is that while the MP-H4 will remain a long iron replacement option only in the UK, the guys at Mizuno USA decided to turn the MP-H4 into a full iron set.
One final note before we get to the pics. Mizuno is one of the sponsors of the MyGolfSpy Tour Staff Contest. In fact, we're giving away 2 sets of Mizuno irons, and the winners will be able to choose any iron from the Mizuno lineup, including the insanely popular MP-59s, the new JPX-825, JPX-825 Pro, MP-H4, or MP-64.
JPX825 and JPX825 Pro