How does anaconda decide to upgrade vs install? (Cannot upgrade F7 to F9)

["Martin Langhoff" <martin langhoff gmail com>]

Using Revisor, I have built an custom install CD that intend will be
able to upgrade a custom F7 system. Anaconda, is missing the cue and
wants to perform a fresh install...

The custom Fedora spins are

 - The current version of the OLPC school server - xs-0.4, based on
F7. Originally installed from a livecd.

 - The development version of the OLPC school server - a F9-based spin.

The existing disk has

    sda1 /boot
    sda2 /
    ... and in /etc/redhat-release it contains the 'Fedora 7 (Moonshine)' string

In the anaconda sources, I am looking at dispatch.py, backend.py and
upgrade.py but it's not 100% clear to me what the rules are.

cheers,




m
-- 
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