Starting with 5.0, we have a summary of the major changes, an enumeration of all new utilities and libraries, and a list of deprecated features for a few of the previous major brlcad releases.
We also have for many releases a collection of all the relevant email traffic on the <brlcad-users@lists.sourceforge.net> mailing list (formerly known as the CAD mailing list).
devs@brlcad.org>