$NetBSD: README.NetBSD,v 1.4 2023/03/27 17:04:42 gutteridge Exp $

Generally, pkgsrc considers the current and previous major releases of
NetBSD to be supported, and older ones not to be supported, following
NetBSD's support notions.  (If as an exception beyond this policy,
NetBSD provides support for an older branch, such as -7 during the
first half of 2020, pkgsrc is likely to follow suit.)

Despite older releases not being considered supported, pkgsrc
generally tries to avoid unnecessarily breaking them.  However, a main
cause of breakage is upstreams of various packages requiring newer
standards, both POSIX and languages.  Thus, even the older of the two
supported releases is likely to be significantly troubled at any given
time.

Beyond the issue of packages building, there is also the consideration
of system infrastructure, such as /usr/bin/make.  If a NetBSD system
has a make which is too old for pkgsrc, one can perform a full
bootstrap.  (Alternatively one could build bmake and use it, as a
workaround.)

As of 2023, it is believed that NetBSD 7 and newer have an adequate
/usr/bin/make; NetBSD 6 and older require a bootstrap or replacement.

Other pkgsrc infrastructure changes may also cause trouble on older
releases.  For instance, by default PKGSRC_USE_SSP is now set to
"strong", which would cause builds on NetBSD 7 and older to fail, as
it passes "-fstack-protector-strong", which isn't recognized by GCC 4.8
or older.