I don't know if people are aware of it. If not, here is a simple trick to see 'what has changed' between two versions of an executable:

ident first_executable_version second_executable_version | sort | uniq -u

For example:

ident db_purge /root/ballen/boinc/sched/db_purge  | sort | uniq -u
     $Id: version_diff.txt,v 1.2 2005/01/18 23:35:50 davea Exp $
     $Id: version_diff.txt,v 1.2 2005/01/18 23:35:50 davea Exp $

I find this very helpful in reviewing what has been modified in the various BOINC daemons, when updating versions.