Ubiquiti just released its new network controller version 7.3.76 and alongside with the major change of jumping from Java 8 to Java 11, the update had a lot of features and changes under the hood added.

Unfortunately Ubiquiti did not release the new controller version via the official apt repositories. In the official patch notes they say "its coming in a later release to debian/ubuntu apt sources":

If you still want to use all the cool new features on your Ubuntu based controller, I quickly mapped out the steps to do a clean update, especially in switching from Java 8 to Java 11, which is one of the major changes under the hood.

Backup, prepare and clean up first: Make sure you have a current backup of your Unifi Controller config file.

Then we can proceed to update our repositories:

sudo apt update

Next stop unifi and check if its really stoped:

sudo systemctl stop unifi
sudo systemctl status unifi

You should see status "inactive" now from systemctl.

Next we uninstall and delete our prvious Java 8 version:

sudo apt purge openjdk-8-*

Then install the new Java 11 version:

sudo apt-mark unhold openjdk-8-*
sudo apt install openjdk-11-jre-headless

We also want to make sure that our Java version is not going to change unless we want it to. So lock it with:

sudo apt-mark hold openjdk-11-*

Great! Now download the debian/ubuntu controller install file 7.3.76:

wget https://dl.ui.com/unifi/7.3.76/unifi_sysvinit_all.deb

...and install it right away with:

sudo dpkg -i unifi_sysvinit_all.deb

The installer will ask you if you have a current backup of your controller file (which we have :)) and after you confirm that it should run the install flawlessly.

Please don't worry if it seems for a while that the install is stuck....it took in my case 2 minutes until it finished.

Now we are ready to start our controller again, it might take a little longer right after the update:

sudo systemctl start unifi

Check if everything went fine with:

sudo systemctl status unifi

If everything looks similar to like in my screen, it was successful! Enjoy all the new features of your controller.