Just a note for anyone trying to load 2026.3 onto a Raspberry pi4 using docker.
If you end up with things appearing to download, but getting an error and the first file extract failing, this will be because your docker version is not compatible with with the archive method now being used by HA.
The solution is obviously to upgrade using the instructions here Debian | Docker Docs which starts with deleting everything to do with docker… If, like me, you are concerned (quite rightly!) that this could result in the total loss of your system, fear not.
My docker installation was originally done using the docker convenience script 5 years ago, and I was unaware that docker was not being upgraded, so was sitting at version 20.10.24, which does not use the required archive method for 2026.3 and above.
I took a backup of my entire Raspberry Pi, and then booted with the backup SD card. Stopped all running containers (HA, MA, mosquitto and zigbee2mqtt), then with trepidation, ran the upgrade as Install using the apt repository, and it worked perfectly!
I have now run the upgrade commands a second time on the live system, and again it has come back perfectly, and allowed the download of 2026.3.1.
So, if you were fearful of losing your entire system by doing the docker upgrade, be assured that it should not be a problem, if you follow Debian | Docker Docs
The added benefit is that apt will now be able to keep docker up to date, so hopefully not a problem in the future.
I hope this is of assurance to someone…