The latest 2018.4.1.2 version comes with a number of security fixes so you should upgrade as soon as possible.
You can upgrade directly from DPBuddy using the following commands (this will upgrade multiple devices at once):
dpbuddy saveAll -device "device1, device2 ..." dpbuddy quiesceDomain -domains ".*" -device "device1, device2 ..." dpbuddy firmware -fromUrl "https://ak-delivery04-mul.dhe.ibm.com/sar/CMA/WSA/082tt/0/idg_lx2018412.lts.scrypt4" -device "device1, device2 ..." dpbuddy connect -device "device1, device2 ..."
The URL in this example is for Linux IDG, please find the right version for your DataPower on Fix Central.
Note that after the upgrade we had to manually reset user passwords.
You may also want to run a command to validate the state of your services and objects after the upgrade:
dpbuddy assertState -domains ".*"