On 01/02/2011 11:04 PM, Joshua Saddler wrote:
> 
> Whatever you folks eventually settle on, please send patches and
> suggestions to the GDP for our upgrade guide. I'd prefer that users
> have a possible upgrade path from *any* profile/version of Gentoo up
> through the present. If you decide not to support anything older than
> version X and require reinstalling or some other set of procedures,
> please let the GDP know via our ML or bugzilla.
>

The current hard requirement is one year:
http://www.gentoo.org/proj/en/council/meeting-logs/20091109-summary.txt

The follow up discussion probably didn't end up in any concrete
decisions. If we want to actually make sure upgrades from old installs
(>1 year) work then we should setup some kind of a bot doing upgrades.
It would then provide the documentation for the upgrade path and make
sure it keeps working.

Regards,
Petteri