cvsup and versions

[wayne mitchell]

hey,
i have just cvsup'ed for first time (newbie)
RELENG_8_1_RELEASE
rebuilt world...
there is a problem with a particular port:
audio/libsndfile
the version in this system ports tree is 1.0.21
the set of versions available within the cvs repository are:
 1.0.20, 1.0.23, 1.0.24 - but not 1.0.21
1.0.24 is latest
it seems that the latest version did not carry across with the cvsup
i have most documentation available
have tried portupgrade - no go
am stuck
how do i update this individual port
and is it possible to have two separate versions of same port in the tree
example: to rename libsndfile dirs to
libsndfile-1.0.21, libsndfile-1.0.24
for sake dependancies
am guessing, though i suspect that the two installed binaries may conflict...