
	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.   Especially INCOMPABILITIES !



	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!)

		If the system has properly working mmap(), it can be
		used on router, and transports to yield some additional
		performance benefits by lowering syscalls (and mapping
		things R/O allows simple sharing..)
		The ROUTER should use switch "-m" on all its "relation"
		definitions of "ordered" and "unordered" types when using
		mmap()!

		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-2.98:

		Changes on sample configs changed the way how  "thishost"
		relation ($MAILVAR/db/localnames -file) is used.

		The  $MAILVAR/db/localnames is now actually a mapping of
		those various names to the desired forms of the canonic
		name, thus an example:

			astro.utu.fi            astro.utu.fi
			oj287                   astro.utu.fi
			oj287.astro.utu.fi      oj287.astro.utu.fi
			oj287.utu.fi            astro.utu.fi
			sirius                  sirius.utu.fi
			sirius.astro.utu.fi     sirius.utu.fi
			sirius.utu.fi           sirius.utu.fi

		The file is to be kept in  sort(1)  order !


	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.
