====== Ubiquiti - CLI - Upgrade Controller ======

1. Navigate to the Ubiquiti [[https://www.ui.com/download/unifi/|Downloads]] page to obtain the UniFi Controller firmware download link.

2. The latest UniFi Controller releases are listed in the **Software** section.

3. Expand the **UniFi Network Controller for Debian/Ubuntu Linux and UniFi Cloud Key** option and select download.

4. Accept the EULA and copy the firmware download URL. An example URL is: <code>
https://dl.ui.com/unifi/x.xx.xx_version/unifi_sysvinit_all.deb </code>

<WRAP info>
**NOTE:**  You can also obtain the firmware link from the Ubiquiti Community [[https://community.ui.com/releases|Software Releases]] page.

Open the relevant UniFi Network Controller **General** or **Beta** release page and copy the **UniFi Controller for Debian/Ubuntu and UniFi Cloud Key** link.
</WRAP>


5. Open a SSH session using your favorite SSH/Telnet client program.

<WRAP info>
**NOTE:**  Access the Command Line Interface on the UCK (Unifi Cloud Key) using SSH. 

See the Intro to Networking - How to Establish a Connection Using SSH article for more information on how to connect to the Cloud Key using SSH.

</WRAP>

6. Navigate to the /tmp directory:

<code bash>
cd /tmp
</code>

7. Verify if there are any previous installation files present in the directory and delete them if applicable:

<code bash>
ls -l
</code>

<code bash>
rm unifi_sysvinit_all.deb
</code>

8. Use the wget command with the previously copied link to download the UniFi Controller installation file and store it in the /tmp directory.

9. Replace https://dl.ui.com/unifi/x.xx.xx_version/unifi_sysvinit_all.deb with the previously copied URL.

<code bash>
wget https://dl.ui.com/unifi/x.xx.xx_version/unifi_sysvinit_all.deb
</code>


10. Wait for the firmware download process to complete and install the new version using the dpkg command:

<code bash>
sudo dpkg -i unifi_sysvinit_all.deb 
</code>

<WRAP info>
**NOTE:** If the UniFi Controller version needs to be downgraded to an older release, then the currently installed version can be removed with the <code bash>sudo dpkg -P unifi</code> command.
</WRAP>


11. Wait for the installation process to complete and remove the unifi_sysvinit_all.deb file afterwards.

<code bash>
rm unifi_sysvinit_all.deb 
</code>

----

===== References =====

https://help.ui.com/hc/en-us/articles/216655518-UniFi-UDM-UCK-How-to-Change-the-Controller-Version-Using-SSH-