Newer and improved
As was pointed out, the 23 series was the last iteration of the Hobart designed machines. It did have the power module wash system and most models had the heat delay on the wash portion of the cycle that ensured the water was heated to an effective temperature to clean the dishes. The 24 series was a direct Whirlpool clone and has continued on until today with differences in features and build components.
John L, based on your experience, what specific improvements did WP make to the 21 series once it was their baby? And did they add the heat delay to the 22 series or only the 23's?