Use this tag for any questions pertaining to Blenders Multiresolution Modifier.
The Multiresolution Modifier (often shortened to “Multires”) gives you the ability to subdivide a mesh similarly to the Subdivision Surface Modifier, but also allows you to edit the new subdivision levels in sculpt mode.
The Multiresolution Modifier is the only modifier that cannot be repositioned in the stack if it means that there will be geometry or other object data created or removed before it (e.g. all Generate, some Modify and some Simulate modifiers cannot come before the Multiresolution Modifier).
For more information, see the Blender Manual