Basically, I got all the apt.sources for each version and upgraded through each version to the next. If you try to jump versions you run into dependency issues.
I always did in following order.
Ver9. or latest version on official image
apt-get update
apt-get upgrade
reboot
apt-get dist-upgrade
reboot
update repos to next version and repeat till you get to final version.
between each reboot i imaged my sd card in case something broke and I did not have to start over every time from official image.
I used gnome-disk-utilities on xubuntu and if supported pishrink to shrink the image file.
If you run into any errors with packages breaking the update process you hold them and then update from last step that completed successfully. That is what my picture from above is from.