[plt-scheme] PLanet should indicate which PLT version is required

Do you suppose the PLaneT web site could tell us if a given .plt package
requires PLT v4 as opposed to v3?  I ask because, in the last few days,
a new package showed up (sorry, I can't remember which), and it only
worked with v4, but I had to discover that fact by trial and error.
-- 
Don't fall into the trap of writing everything as though it
were a cell phone text message.
        -- Karl Fogel, "Producing Open Souce Software"