Degrade, upgrade

[Phil Brennan]

On Thu, 22 Jul 2004 15:06:02 +0200 (CEST), Kovács Péter
<kovacspeter2 at freemail.hu> wrote:
> Hello guys,
> 
> I have a system running FreeBSD 5.2.1 and want to degrade it
> to FreeBSD 4.10 (because the program I want to use only runs
> and supported on that platform) without reinstalling the system.
> Is it enough to cvsup to the RELENG_4 branch and recompile
> the system?

You will also need to run mergemaster, and for such a drastic change,
you will probably just have to take the default configs from 4.10, as
it would be difficult to merge them manually. I could be wrong though,
as I haven't tried a downgrade, currently planning the opposite :)

> Should I recompile all the programs that were previously
> compiled in the FreeBSD 5 environment?
> 

I think so, yes. FreeBSD is pretty good at backwards compatibility,
but forwards compatibility is a bit more difficult :) Its quite
possible that some of your programs would work without recompiling,
but where API's or simply names of libraries have changed, you will
run into problems. Its best to do this to avoid headaches later on.

> I would also like to know how this works backwards (which is
> the common way), so to upgrade from 4 to branch 5. Is there
> some kind of tutorial for this?
> 
I've not had any problems running freebsd4 programs on 5, so I can't
help you there, sorry.