Debian Jessie dist-upgrade or clean Bullseye install
 

This is the computer I use everyday, and I know I should have upgraded before but I'm doing it now, so if I do a "dpkg --get-selections > dpkglist.txt" and backup my /home then restore them after a clean install of Bullseye could I get close to my current apps and settings? I know some tweaking will be needed and I'm prepared for some packages to not be installed for one reason or another, but for that scenario how could I tell which packages were not installed? I'm not sure I could dist-upgrade Jessie through Bullseye without something breaking or just taking to long.

If you make sure to include the hidden dot-config files in your /home and any config files in /etc that you have modified, you should be able to restore your settings.

So as a test when Bullseye was released I did an install of Jessie in a VM and upgraded it through Stretch, Buster, and to Bullseye. Mind you, this was a minimalistic install with just a base install + KDE, but it was able to dist-upgrade up to Bullseye and still work.


Not saying it's the best choice, but I have done it before and it did work. I had attempted with Wheezy and that didn't go so well for me.

My take:
Minor versions = upgrade
Major versions = fresh install

Fresh install removes clutter, and reduces chance of package compatibility issues that may arise from upgrade.

I've changed quite a few /etc config files over last couple years and I can't remember them all, any ideas how I might discover them?

No idea. But whenever you change files it is recommended to save the original and if you have done that then you should be able to find out which files you have altered. On your next installation trip keep a log file of which files you will be altering, or even better, make copies of the altered files and keep them in your backups. This is what I usually do as this also saves my configurations.

I have more than 20 Bullseye installations. Nearly all started out life as Jessie or Stretch, and were live upgraded via apt-get. I back up in place most /etc/ config files before editing, and backup the new too. e.g. /etc/initramfs.conf I save as .initramfs.conf01, and my edited version as .initramfs02. It's been very rare that any such edits actually has caused any detectable issue.

Just compare the contents of dpkglist.txt to the output of dpkg --get-selections on the new system.

Note that along with the package list, you may want to make a backup of the debconf database.
This will preserve whatever answers you've ever given when installing or configuring a package.
Additionally, I'd suggest making a backup of /etc/ that you can refer back to if needed.

Skipping versions is not supported (or even recommended). You'd need to upgrade three times. jessie->stretch->buster->bullseye. And you should read the upgrade notes for each one.

Evo2.

Thank you! Your reply reminded me that when I edit config files under /etc that I ether leave the original with .orig or .bak, so they were easy to find and there weren't as many as I thought just the same ones over and over.

Thanks for the tip on including debconf-copydb, I've never heard anyone mention it before. For extra insurance I'm making a clonezilla image of everything.

I didn't say I could skip a release, I said "Jessie through Bullseye".

I didn't say you did.

True and that's when I realized your reply could help those who have the same questions and found this thread, so information that I summarized you included.

From memory, there were some big changes when Buster came out, & it was recommended that a fresh install was the way to go, so I'd suggest a fresh install of Bullseye.

From what I've been hearing I believe I will. I use xfce do you think I could get similar settings experience if I grab a list of the installed packages and copy my home to a new Bullseye install? If not all packages are installed and I have all my old home directories & files including hidden in the new home will things straighten out after a few reboots?

I cannot confirm this.
I've been doing stable=>stable distribution upgrades on my server since squeeze=>wheezy.
It now runs bullseye.
I haven't seen that recommendation anywhere before or during the latest.

That said, these were all timely (before oldstable ran out of support) upgrades, one by one.