Just to make sure I do not overlook some existing hidden backward
compatibility: Is it correct and intentional that RPM 4 cannot read RPM
5 source packages at all? Or in other words: to upgrade an installed RPM
4 one cannot just "rpm --rebuild" the SRPM of the RPM 5:

| $ openpkg rpm --rebuild openpkg-4.0a0-20071229.src.rpm
| Installing prj/openpkg-2008/src/framework/SRC/openpkg-4.0a0-20071229.src.rpm
| error: source package expected, binary found

If all this is intentional (and I personally do not have any problem
with this), I currently know two upgrade possibilities: to provide a
SRPM of RPM 5 which was still rolled with RPM 4 or to use rpm2cpio from
RPM 4 to unpack the RPM 5 SRPM (which still works as I figured out) and
then do a plain "rpm -bb *.spec" to build and install the new RPM 5
(both assuming that the RPM 5 *.spec itself does not use any features of
RPM 5 and is still fully compatible with RPM 4).

Can this be confirmed?

I don't want to go into the wrong direction
regarding my distribution upgrade plans...

                                       Ralf S. Engelschall
                                       rse@engelschall.com
                                       www.engelschall.com