Arte di Mano cases for Leica M-P: Old M case works, just
Since the introduction of the Leica M-P with the reinstated frame line lever there has been some doubt about whether existing M half cases would fit. I understand that some cases, including Leica's own, do have problems accommodating the lever. With Arte di Mano cases, however, the situation is a little more flexible. I own both the standard half case and the special edition which covers the Leica grip. In my opinion these cases are absolutely the best money can buy.
I've tried both on the new M-P and I think the fit is just about acceptable. While the edge of the case does touch the lever, it doesn't overlap and is not unsightly. I suspect that if you already own an M case from Arte di Mano you could happily use it with the M-P. It is certainly worth trying before you go out and buy a replacement.
I had a word with Sejun Kim of Arte di Mano in Korea and he confirms that it is possible to use the old case on the M-P although there could be some loss of functionality of the lever. However, he is a perfectionist and is currently working on a new M-P case which will feature a slight change in the contour of the front cover to fully accommodate the lever. He also tells me that it is not possible, for various reasons, to amend the old cases.