Reason for fixing minimum bootstrap version at 2 major releases ago?

[Matthias Kilian]

Hi,

On Tue, Dec 13, 2016 at 12:48:25PM -0500, Shea Levy wrote:
> I'm wondering, why do we require ghc to be bootstrappable with the past
> 2 major releases instead of just the past 1? Is it a common case that
> someone is compiling GHC but can't easily get the latest release?

Well, I can't speak for those who made this decision, but supporting
more than one major release eases the life of os distribution package
maintainers, especially in cases where the distribution package had
been left behind for too long, which may happen for many reasons,
like a maintainer dropped maintainership and a new one has to be
found first, or like a maintainer missing a major release because
he's to busy or too lazy. (The latter sometimes applies to me ;-))

Ciao,
	Kili