Define upgrade?
Code:
sudo apt update
sudo apt upgrade
should keep you current.
If your speaking of the mainline kernels: https://kernel.ubuntu.com/~kernel-ppa/mainline/
You'll have to install those by hand.
EDIT: your kernel will stay as updated as your zfs allows it.
EDIT2:
Code:
zpool status && df -h /me1
pool: me1
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
me1 ONLINE 0 0 0
sdb ONLINE 0 0 0
errors: No known data errors
Filesystem Size Used Avail Use% Mounted on
me1 56G 128K 56G 1% /me1