⚠️ If you're running Debian 11 (bullseye) or Ubuntu 20.04 (Focal Fossa), the new versions of Power Mail-in-a-Box will continue to work for you. No further action is needed for now.

As you know, Ubuntu 22.04 (codename Jammy Jellyfish) has been out for a while, and I've been working towards updating Power Mail-in-a-Box compatible with it - so that you're able to use it on a fresh image with recent software.

While a Ubuntu Jammy-compatible release is just over the corner, some of the pieces of software that have been updated so that they run on Jammy do not run on Debian 10 (buster) - which is the oldest Linux distribution that is currently supported at the time of writing. Details in #47 and #59. Therefore, the day Ubuntu 22.04 becomes supported is the day Debian 10 becomes unsupported.

I am running Debian 10 - what now?

The plan is to bring you to the next version of Debian - Debian 11 (bullseye) - which will remain supported for the while being.

There will be some downtime - the upgrade process can take 1-2 hours at most (assuming nothing goes terribly wrong), but experienced folks can probably get it done within 30 minutes. You will need to SSH into the box to perform this upgrade.

Upgrading from Debian 10 to 11

1. Make sure that within Debian 10 everything is as up-to-date as possible. The Power Mail-in-a-Box setup script updates all packages via apt so all we need to do is run it again:

curl -L https://power-mailinabox.net/setup.sh | sudo bash

2. Make one final backup and make sure you have access to it outside the box (including the unlocking key). You hopefully will NOT need it, but if something goes really bad, you can always recover your precious data.
3. Edit the APT source list - this list tells APT (which is the tool that installs software to the box) how to know what software is available to be installed and how to know how to get it.

sudo nano /etc/apt/sources.list

3. 1. You should be presented with a text editor, showing something like this:

deb https://example.com/debian buster main
deb https://example.com/debian buster-updates main

3. 2. Wherever you see buster, replace with bullseye. In our example, the text editor will be looking like this:

deb https://example.com/debian bullseye main
deb https://example.com/debian bullseye-updates main

3. 3. Save the changes to the file and exit - if you're on nano, that's pressing Ctrl + X then pressing Y;
4. Update the source lists, and then upgrade the packages:

sudo apt update

sudo apt upgrade --without-new-pkgs # This particular step is optional, but Debian maintainers recommend it
sudo apt full-upgrade
sudo reboot

5. If everything goes right, after the reboot you should be in a brand new Debian 11 environment! All your data is still there as you left it. All you need to do now is upgrade Power Mail-in-a-Box to the latest version again:

curl -L https://power-mailinabox.net/setup.sh | sudo bash

This guide was based on the official guide that can be found here: https://www.debian.org/releases/bullseye/arm64/release-notes/ch-upgrading.en.html