Distributions

This is different.
They tell you how to get the latest version, they do not tell you that you should not use distro version.
(it should be noted that lot of linux users are running very old LTS release like Ubuntu 18.04 which can be annoying to upstream, but it is not the distributions fault).

Mutt
"Figure out if you have a mutt installed already by entering "mutt -v" at the prompt. If you have none yet, or the displayed configuration doesn't suit your needs, grab the source from http://www.mutt.org/download.html and "do it yourself": install mutt."

DWN
"Because dwm is customized through editing its source code, it's pointless to make binary packages of it. This keeps its userbase small and elitist. No novices asking stupid questions. There are some distributions that provide binary packages though."

PANDOC
"Check whether the pandoc version in your package manager is not outdated. Pandoc is in the Debian, Ubuntu, Slackware, Arch, Fedora, NixOS, openSUSE, gentoo and Void repositories."

LaTex
"Check your Linux distributions software source for a TeX distribution including LaTeX. You can also install the current TeX Live distribution directly---in fact this may be advisable as many Linux distributions only contain older versions of TeX Live, see Linux TeX Live package status for details."