We now have S/MIME support

The rest of this section needs updates too, preferably just to point
back to the RT::Crypt docs and improve them if needed.
Make the versioning of RT/RTIR clearer
Disable was unclear, overwrite is closer to what happens
Be more direct about version support and upgrades

Only newer releases, not "any other" release.
This is RTIR, the upgrade will be more complex, you will need to read
the steps.
Remove references to TicketLocking and TicketAging

The former mostly works on 4.2, although hasn't had a release (and needs
RTIR specific features).  The latter looks like a nightmare to upgrade
because of how it was implemented and it hasn't been maintained in
years.
DocIndex is really horrible, there's no reason to point to it

The top level of /docs/rtir/ that we point to is better organized.
There's no reason to use OnlineDocs

All the docs are on docs.bestpractical.com with much better rendering.
Add more pointers to www.bestpractical.com/docs/rtir/

Standardise on 3.2 rather than latest since we want 3.2 users to 3.2
versions of the docs, not say 3.4 versions.  Most other links are L<>
so interlink better.