post_install() {
    dkms install -m sixfireusb -v ${1%%-*}
}

pre_upgrade() {
    local curver=${2%%-*}
    # $2 is unset due to a bug. See, https://bugs.archlinux.org/task/32278
    # Query current version using pacman as fallback
    [ -n "$curver" ] || curver=$(pacman -Q sixfireusb-dkms | cut -d' ' -f2)
    pre_remove $curver
}

post_upgrade() {
    post_install ${1%%-*}
}

pre_remove() {
    dkms remove -m sixfireusb -v ${1%%-*} --all
}