Excerpts from the release notes:
* ssh-agent(1): PKCS#11 modules must now be specified by their full
paths. Previously dlopen(3) could search for them in system
library directories.
* ssh(1): allow forwarding Unix Domain sockets via ssh -W.
* ssh(1): add support for configuration tags to ssh(1).
This adds a ssh_config(5) "Tag" directive and corresponding
"Match tag" predicate that may be used to select blocks of
configuration similar to the pf.conf(5) keywords of the same
name.
* ssh(1): add a "match localnetwork" predicate. This allows matching
on the addresses of available network interfaces and may be used to
vary the effective client configuration based on network location.
* ssh-agent(1): improve isolation between loaded PKCS#11 modules
by running separate ssh-pkcs11-helpers for each loaded provider.
* ssh-agent(1), ssh(1): improve defences against invalid PKCS#11
modules being loaded by checking that the requested module
contains the required symbol before loading it.
* ssh(1): don't incorrectly disable hostname canonicalization when
CanonicalizeHostname=yes and ProxyJump was expicitly set to
"none". bz3567
Full release notes at https://www.openssh.com/txt/release-9.4
Relnotes: Yes
Sponsored by: The FreeBSD Foundation