FreeNAS/BSD Jail with FUSE

I wasn’t exactly sure what category this fit in and noticed a few other FreeNAS posts were also uncategorized as well. So if this should be in a specific category please correct me.

I was trying to mount a FUSE based file system within a Jail. I’m on 11.3-U2.1 (as of writing I believe that is the latest stable version).

Upon attempting to mount I received this error:
Fatal error: failed to mount FUSE fs: open /dev/fuse: no such file or directory

I found some hints showing that in order to do this you need to set the following three parameters for the jail:

enforce_statfs = 1 (default is 2)
allow_mount = true (default false)
allow_mount_fusefs = true (default false)

I tried this and it didn’t work. I read the hover text on allow_mount_fusefs in the jail wizard and it states that allow_mount and enforce_statfs need to be set appropriately and it needs to be a jail on release 12.0 or later.

I find this strange as further digging hints at it being a bad idea to run newer versions in the jail than the host’s version. If that’s the case, why even bother putting allow_mount_fusefs in the wizard?

It’s documented here: https://www.ixsystems.com/documentation/freenas/11.3-RELEASE/jails.html#jail-jail-props-tab (search for fuse)

I see fuse mentioned here on a change log for FreeBSD and the test plan indicates this person did it in 11.2 but with a modified iocage: https://reviews.freebsd.org/D16371

So I suppose the big question from this is, if it’s not odd that allow_mount_fusefs is an option in the wizard, is it possible to run a 12.0 release jail on 11.3 and if so what could be the repercussions of doing so?