How long are old pkgsrc releases supported?

[Frank Wille <frank%phoenix.owl.de@localhost>]

Hi,

in 2018 I have set up a new NetBSD server and compiled lots of packages
with pkgsrc-2018Q2. Currently it is running NetBSD 8.2. Yesterday I noticed
that I need to install print/tex-tetex, but it no longer works:

Requesting http://ftp.NetBSD.org/pub/pkgsrc/distfiles/tex-tetex-47198/tetex.tar.xz
ftp: Error retrieving file `404 Not Found'

Needless to say that I didn't find a 47198 tetex.tar.gz anywhere else on
the net. :|

On ftp.netbsd.org I see 2019Q3 as the oldest pkgsrc. Does it mean that
everything older than half a year might vanish without notice?

I cannot build, test and configure hundreds of packages every few months
on an important live-system (company web- and mail-server) just because I
might want to install a new package some time later!?

-- 
Frank Wille