TL;DR There is now just one recommended Colemak-DH variant.

The mapping from the original Mod-DH release (with M in the home row, usually known now as Colemak-DHm) is now the recommended and supported layout for all keyboard types.

Why?

A bit of history: The original Mod-DH was release in 2014. Following that, a number of variants were proposed and used, which ended up causing a confusing situation for newcomers, and leading to a desire to standardize on one variant that everyone could live with, focused primarily on optimizing for standard staggered keyboards. That variant switched the M and K keys compared to the orginal DH, and became the recommended layout from 2017 onwards for standard boards. Let's now call that variant Colemak-DHk. The original mapping became known as Colemak-DHm, and continued to grow in popularity among folks with ergo keyboards.

The situation has since evolved, so let's take stock:
- The Mod-DH project site has been promoting the default Colemak-DH (now DHk) on staggered boards, but Colemak-DHm on Ergo and matrix-like boards.
- Potential newcomers have to learn about the two variants and why they exist, and then pick one based on their anticipated hardware usage.
- The DHm variant and ergo boards in general have grown significantly in popularity since the previous revision was made in 2017.
- Having two variants creates an unsatisfactory situation for people who start using DH on a staggered board, and then later migrate to an ergo board.
- Two layouts have to be supported by people like DreymaR, myself and others who maintain related software and resources.
- Although the DHk variant is still thought to be slightly better on a staggered board, difference between the two is extremely minor - just M and K - and the difference in quality between those two keys is small (and somewhat subjective). On matrix or column-staggered boards however, there is a noticeable benefit to having M in the middle row.

This issue has been discussed on the Discord and the forum recently, and has lead to a clear conclusion: maintaining two layouts with such a small difference is not worthwhile. There should be just one "DH", and the one which provides the best overall experience across all board types is "DHm". This decision effectively reverts the change made in 2017 to switch the M and K for staggered boards.

I recognise this change might not be popular with standard keyboard users who are using what is now called the "DHk" variant. Those users may continue (especially if they don't plan to migrate to an ortho board) as it obviously still works great on staggered boards, and I'll keep the existing downloads for the "DHk" variant. However the default for future newcomers will be "DHm" on all hardware types. DreymaR will be supporting "DHm" as the new standard Colemak-DH in his Big Bag too.

I have updated the Mod-DH project pages to reflect this.

Happy DH'ing