Postgres ODBC driver versions
I found the following in the source code:


  This is version 07.05.0001. For those that don't know or don't
  recall how the versioning works, the major and minor number track
  the latest release of PostgreSQL that the driver is expected to work
  with. The revision number is a bit more complex. The first two digits
  are the version number, where even numbers are development versions,
  and odd are release. The last two digits are the build number.
  
  In other words, this driver is build 01 of development version 00, and
  is expected to work with PostgreSQL 7.5dev. :-) The leading zeros are
  an ODBC thing...


I guess one cannot get any better answer than this :)