Is it possible to install old packages on new release

[Igor Zinovik]

       Hello, misc readers.
Maybe my question is obvious, but i want to know could one install old packages
on new release? My situation is following: i have OpenBSD_3_8 and a lot of
packages on CD with OPENBSD_3_6. Docs say: "Dont mix OpenBSD system and ports
version, keep system and ports in sync", but it dont say anything about 
packages.