How to upgrade Debian 9 Stretch to Debian 10 Buster and how to update 3CX Server from V16 to V18

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This is no small update, so you should plan for a minimum of approx. 18 minutes of downtime. This all depends on your system specs and how much data you have on your 3CX (e.g. recordings, voicemails). If your full backup size is anywhere above 500mb, you should plan for half an hour or more.

Several of our customers that are using GCP (Google Cloud Platform) to host their 3CX, tend to have issues with the 3CX service binding to the private IP interface allocated to them by GCP. Plan your time accordingly to allow for a fresh re-install of 3CX and restore from a backup.

A few of our customers that host their own 3CX systems have reported the digital receptionist prompts are missing after updating:

https://www.reddit.com/r/3CX/comments/pav39z/psa_v18_removing_dr_prompts/

1. Create a Backup and download the .zip file

Create a backup and download the newly created .zip file. Make sure you save it somewhere safe, such as your Desktop or Downloads.

2. Make sure you are updated to the latest release of 3CX V16

The latest version of 3CX V16 is the 16.0.8.9 build. "3CX Version 16, Update 8 FINAL" is the required version to install before the "upgrade Debian from 9 to 10" option is available in the 3CX Management Console.

3. Watch the email address you have configured for notifications

Watch the email address you have configured for notifications, as failure notifications and logs will go here.

• Note: you will also find Generic failure notifications in the 3CX MC Dashboard > Event Log

4. Update / Upgrade from the 3CX Management console

Once you are positive you have a backup downloaded to your local machine, navigate to the 3CX Management console.

• Select "Updates" in the top right corner. You should see "Version 18 (Includes OS upgrade from Debian 9 to 10)"

• Select the blue "Upgrade" button when you are ready to proceed.

5. Things that tend to cause failures / troubleshooting

• in apt: "Preparation: Found an uncommon source list in /etc/apt/sources.list.d/:"

• No network connection after reboot? Check /etc/network/interfaces for "pre-up iptables-restore /etc/iptables.rules" (This needs to be removed from the /etc/network/interfaces file, then you will need to reboot.)

• Your Hosting Provider should give you access to a VNC "Console" to manage the VM. For on-premise installs, use a monitor and keyboard to check the /etc/network/interfaces file.

• If you are have custom iptables set, check what the equivalent is in nftables and see if they were translated correctly.

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