how to get older version instead of bleeding edge

["HG" <henri@broadbandnetdevices.com>]

Hi all

How I get the older version of the linux for mips kernel , in particular I
would like the 2.4.20

after downloading successfully the latest cvs with the web example
i tried to upgrade with : $ cvs
cvs -d :pserver:cvs@ftp.linux-mips.org:/home/cvs  update -r2.4.20 linux
a long list of ..../filename is no longer in the repository was obtained

any hints of the command line necessary

thanks

Henri