Usage of Recommended and Optional packages

[larsen0815]

https://www.mailpiler.org/installation/ states some recommended and optional packages:

Recommended attachment extractor utilities:
catdoc
pdftotext
unrtf
tnef
xlhtml (with sj mods)

Optional:
memcached
clamav
libpst

I can imagine the usage of some, but it would be nice to know in which case I should install each extra package.

[jsuto]

Well, the deb package expects (and actually installs most of these). Libpst seems to offer pst support up to outlook 2003 format (pretty ancient), and recently clamav support has been removed from the code. Memcached may or may not offer some benefits.