
	Some notes on upgrading to the newer ZMailer releases

	On many cases the internal structures have changed a bit, while
	the external interface has remained the same, however there are
	cases when change is major rendering previous (spool-)files, and
	subsystem programs incompatible.  (At least partially.)

	These notes are to make you aware of things that have
	changed since previous versions.   They don't report on
	all "minor" things, like how router .cf -files were
	altered, and how the database usages changed due to that...


	ZMailer-2.99:
		New ZMSH command primitives:  ssift, tsift
		Actually the "tsift" is the old "sift", and the
		old name is still valid, though depreciated.
		(Now can do  sendmail-like regexprs as well!)

		Changed the transporter locks.  The end result
		is that old-style locks will NOT become unlocked
		by the scheduler, and that may cause problems
		in some cases.    It requires MANUAL edition of
		such locks on  $POSTOFFICE/transport/* -files.
		("^r~[a-z]" is a regexp to find them.)
		Change the "~" to " " to unlock.   The Scheduler,
		and transporter programs must be turned off.

		All binaries MUST be of the same version!

	ZMailer-2.96:
		Introduced the DSN (Delivery Status Notification)
		things on the transporter subsystem (well, everywhere),
		and caused some non-backward compatible changes.
		(You MUST have ZM-2.96 binaries all thru!)

	ZMailer-2.94:
		Introduced the IETF-NOTARY diagnostics in between
		the transporters, and the sceduler -> must have
		binaries of this version on the transports + scheduler.

		The "canned" error messages MUST follow the model:
			HDR From: <mailer-daemon>
			SUB Subject: canned error message
			HDR Cc: The Post Office <postoffice>
			HDR Precedence: junk

			message contents..

		That is, for the error reporting to work, the old
		$MAILSHARE/forms/* -messages MUST be edited to have
		those HDR/SUB tokens in their front.
