Some of you may have noticed that the .mcz files for packages that have 
been around for a while like Seaside and Monticello are getting very 
large and taking an extremely long time to load.  This is due to a 
nasty bug in the storage of version info that's been around for a 
while.  A few releases back, I fixed the bug but disabled the fix 
because it broke backwards compatibility (versions written with the bug 
fixed cannot be read by MC versions that still have the bug).

At this point, there have been enough releases that know how to read 
the bug-fixed format that I think I'm safe to enable it for writing as 
well.  So I've just posted a new version of MC (123 on SM) that is both 
in the fixed format (you'll notice it's a much smaller file) and writes 
new packages with it.  If you still have an MC earlier than release 86 
you will not be able to upgrade directly to this version, nor will you 
be able to read the packages it writes.  Anyone that's upgraded MC in 
the last few weeks should be fine, however.

I really recommend doing this upgrade.  As an example, the 'version' 
file inside the zipped packages for recent versions of MC itself was 
almost 4MB (!).  With the fix it's down to 26k.  With compression this 
doesn't make as large a difference to the final file size as you might 
think, but it sure does slow down loads.

Cheers,
Avi