If you have MCL 2.0, here's what you need to upgrade it to 2.01.

This folder contains an updated version of the ptable init. Please 
replace any older versions that may be in your Extensions folder.

To install  MCL patch 1, MCL patch 2, and the Quadra AV patch, create a 
folder called "patches 2.0" in your MCL folder, put the patch1 and patch2 
files into it, start up MCL 2.0, 
then type:
    (ccl::load-patches)
	  (load "cyclone-cursor-patch")
    (save-application "MCL 2.0p2" :init-file "init")

The folder "2.01 sources" contains a variety of updated source files 
(from the  "Examples", "Library" and "Interface Tools" folders) for MCL 
2.0. Just merge the files into the corresponding MCL folders (be careful 
here -- some of the folders contain subfolders, and you must merge their 
contents into the corresponding subfolders as well). Finally, start up 
MCL and type:
 
    (reindex-interfaces).