Upgrading an external package in pfSense
I installed a package like this:
pkg add http://pkg.freebsd.org/freebsd:10:x86:64/release_3/All/ossec-hids-client-2.8.2.txz
…since in pfSense, the default FreeBSD 10.3 repositories are not included in /etc/pkg/FreeBSD.conf.
I was just wondering what my options are for keeping this package up to date in a setup like this? I can't really un-install and re-install all the time as it will most likely result in loss of data.
That depends on what you mean by "keep this package up to date".
If you mean keeping the package itself current/updated, there is no way to keep it updated that does not also potentially compromise the integrity of the package set on pfSense. One of several reasons we do not recommend installing packages from other repositories, including FreeBSD's own repositories.
You can reinstall it by hand when you know an update is available. FreeBSD packages are good about not clobbering your own files/data when uninstalling/updating/installing again.
If you mean keeping it across pfSense updates, that's even less certain. You will likely have to manually reinstall it after each update.