Is there a reason you posted the same text twice?   I could edit it but would prefer that you correct your own post.

Thx, i edit it. No just a copy paste to not loose when connection is lost.

Why ?
- Because for me it’s the best way to see troubles, and things need to be improve.

How ?
- I just follow like a stupid idiot the https://devuan.org/os/documentation/dev … e-to-ascii

What ?
- Debian stretch server with some services comes from debian repo and some others.

Services :
- slapd
- postgresql (main databases)
- mariadb (only one)
- apache2 (with mpm_itk )
- fusiondirectory
- gitlab (with apache)
(and others)

Services from other repository :
- jenkins

Websites (not from repo) :
- nextcloud
- dolibarr
- dotclear
- kanboard
- cakephp base website

Results :

- Migration works
- Post migration tasks not working as we can expect. «Causes are not only devuan»

From the wiki :

Some packages need libsystemd0. Because they need X i guess so when i try

 apt-get purge libsystemd0  

some package want to be remove.
In my case they are ffmpeg* gitlab* libavdevice57* libpulse0* libsdl2-2.0-0* libsmbclient* libsystemd0* openjdk-8-jre* openssh-server* php-fpm* php-smbclient* php7.0-fpm* postgresql* postgresql-9.6* postgresql-contrib* postgresql-contrib-9.6* samba-libs*

Maybe i have done something wrong ? Or it’s just the fact i use package not systemd free ready.

An other point not devuan related but can be usefull before a upgrade. When you purge mariadb scripts keep databases but not when you purge postgresql.

And for the end it’s look like my install is broken at least some part because   

sudo -u www-data php ./occ integrity:check-core

from nextcloud it crash. But i think it’s not devuan related but  php-fpm vs libapache2-mpm-itk. (i will investigate)

I hope this post can help.