Okay here we go. Marco_105 is right and even my idea of the old version was right also ...
So first I just tested how I've done my own high heels. Well basically I've done that with a fake method by creating the feet again in another position and after it I use the delete groups to delete the feet of the character itself. The second part is, that I created a texture including the toes. So I've 3 textures because all my girls have a different skin. I simply can copy one foot from the original skin to the location, because UV geometry stays the same. This will also work for the standard skins.
When putting these shoes back to Blender you have the problem, that the catmull clark algorithm (smoothing) is shrinking the geometry slightly, so that a gap between these shoes and the character will appear. So I made a little bit of overlapping geometry. But in the end I reconnected the vertices in Blender, which is also possible. In this case the shoe becomes part of the character and no gap will appear.
So here are three different versions, first one generated with an old version of makeclothes, one with the current version and one with the current one using additional rigid groups for left and right foot.
First I made the WHOLE foot rigid only leaving out a loop of vertices near the ankle (where the shoe ends). This looks really good, but do not change the position of the foot then ... weird deformation will appear. So that was a rather silly idea. Therefore I decided only to make the area of toes rigid. Here is a picture how it is done:
1) First create two vertex groups on the human
and the shoes. In our case *rightrigid and *leftrigid. The * in front of the group has an extra meaning. Only use dimension, do not deform ...
2) Push the button "Create vertex groups" on clothes (one shoe then is assigned to the left group, the other to the right one. The mid vertex group should not be there).
3) Now select all the faces you want to put in the rigid group on one side (in the example the right side). I know that this might be annoying. Remove these vertices from the right group. Then assign the vertices to *rightrigid instead. No vertex is allowed to be in more than one group on the clothes.
4) On the human: select exactly 3 vertices. These will be used for calculating the dimension, so the outside should be okay for it. Put these 3 vertices additionally to the *rightrigid group of the human (on the human a vertex is allowed to be in more than one group).
5) For my kind of shoes put the selected vertices of the last picture into the delete group to make the original foot invisible.
6) do not forget the second shoe
Since the method works for my shoes, this method should also work for other shoes as well.
Are you interested that I put the heels and pumps into the assets? The method of throwing away the original foot and creating a new one is rather weird, I know.
If I should do it, I will only do that for one standard skin, so that you have to create the other skin versions in the materials yourself- But this is rather simple, copy the Image-file and use a paint program like photoshop or GIMP and replace the foot, then create a .mhmat file with the path to this image file ... and there you have a second material ...