As to the first question it will not happen automatically. Either start anew or clone your card and follow one of the Stretch → Buster upgrade guides on the web. I did this on an Odroid C2 and it worked fine but no guarantees, hence trying it first on a cloned SD card.
I’m sure the Stretch version of DietPi will continue to be updated for a while but only MichaIng can answer that question.
It is generally not recommended to do distro (Debian) major version upgrades. I mean in most cases it works well, perhaps some manual config adjustments required but nothing urgent. But in rare cases issues CAN be much larger. For this reason no distro would ever automate this upgrade, nor support it, neither do we.
I will see if I can sum up all relevant information in our Wiki or here in a sticky thread + give some more details about which software titles would definitely require a reinstall due to distro specific packages/configs outside of what APT does.
We will neither officially support this, nor invest much time to do individual support if issues occur. However as many users will do it regardless, it makes sense to help with useful information to avoid them running into issues that are expected to occur in the first place.
There is no dietpi-update Buster channel. Debian distro versions and DietPi versions are handled independently. The current DietPi v6.25 supports Debian Jessie, Stretch and Buster. Due to the recent official Debian Buster release, meaning it changed from testing to stable suite, the upcoming DietPi v6.26 supports Debian Stretch, Buster and Bullseye (new testing version).
The last two commands I provided via the link (alternatively a reboot) assure that DietPi scripts detect the system as being Debian Buster and properly do software installs and other steps in a Buster-compatible way.
I understand to install a fresh dietpi buster image from scratch, but afterwards do I realy have to setup, install and configure everything new then? I mean all the servers and services I have on my strech image. Is there not something like a migration tool available?
Without apt-get dist-upgrade/apt full-upgrade it wouldn’tbe possible .
I’m glad that it went well for so much users. Also from what I read around it seems to be much safer since Buster. I just remember Wheezy => Jessie which was a catastrophe in my case and Jessie => Stretch which as well left much setup/configs in the middle, where the old configs simply didn’t match 100% to what is expected in Stretch. But it seems that with Buster devs are taking care more carefully the transition, package pre/postinst-wise.
Probably we can offer a script that does distro upgrades in the most careful way, including possibly necessary software reinstalls and placing some flag that we can track this on bug reports .
yes Stretch is still supported with DietPi scripts. However it could happen that Debian software packages will not be updated anymore. But this is out of DietPi control as DietPi is taking care on their own scripts only.
The rule of thumb is, the less software installed on your system, the higher chance for a successful upgrade. The chances for a successful and fully functional upgrade are decreased by a number of 3rd-party packages installed on your current system. From this reason, remove any obsolete standard repository and 3rd-party software before you attempt the upgrade. The aptitude command might help you to find any 3rd party software package currently installed on your Debian system.