The explosive growth of the Internet, coupled with the universal acceptance of email as a desirable form of communication, guarantee that sendmail will continue to evolve and improve for years to come. Well before the release of V8.8, Eric was already thinking about V8.9. To glimpse some of what is in store, look at the file KNOWNBUGS distributed with the source. Note that some of the problems listed are thorny in the extreme and difficult to solve.
Also, percolating constantly in the back of Eric's brain is something he calls "Son of Sendmail" (or sos), a complete rewrite of sendmail from the ground up targeted for the far future. Those of you who have followed the evolution of the source may have noticed that functions are constantly being redesigned to make a future, massive rewrite easier and more modular.