Hi Alexis,

You cannot have xfce4-power-manager from angband.pl installed
together with Devuan's upower. Also angband.pl xfce4-power-manager
dependencies are not strict enough to prevent upower from Debian Jessie
(0.99.1-3.2) being considered as candidate.

I guess, if you do not pin, this situation is too complicated for
apt-get/aptitude resolver.

But there is no problem with Devuan (except maybe that it adds epoch to
upower which IMHO could be avoided).

It seems you have problem because you are mixing various sources and do
not have appropriate apt pinning setup.

petr:~$ apt-cache policy xfce4-power-manager upower
xfce4-power-manager:
  Installed: 1.4.1-1
  Candidate: 1.4.1-1
  Version table:
     1.6.0-1 0
         -1 http://ftp.cz.debian.org/debian/ experimental/main amd64
Packages 1.4.4-4 0
        400 http://packages.devuan.org/merged/ ascii/main amd64 Packages
        300 http://packages.devuan.org/merged/ ceres/main amd64 Packages
         -1 http://ftp.cz.debian.org/debian/ testing/main amd64 Packages
         -1 http://ftp.cz.debian.org/debian/ sid/main amd64 Packages
     1.4.1-2.0nosystemd1 0
        500 http://angband.pl/debian/ nosystemd/main amd64 Packages
 *** 1.4.1-1 0
        999 http://packages.devuan.org/merged/ jessie/main amd64
Packages -1 http://ftp.cz.debian.org/debian/ jessie/main amd64 Packages
        100 /var/lib/dpkg/status
     1.0.11-2+b1 0
        100 http://ftp.cz.debian.org/debian/ wheezy/main amd64 Packages
upower:
  Installed: 1:0.9.23-2+devuan1.2
  Candidate: 1:0.9.23-2+devuan1.2
  Version table:
     1:0.9.23-2.0nosystemd3 0
        350 http://angband.pl/debian/ nosystemd-stretch/main amd64
Packages *** 1:0.9.23-2+devuan1.2 0
        999 http://packages.devuan.org/merged/ jessie/main amd64
Packages 400 http://packages.devuan.org/merged/ ascii/main amd64
Packages 300 http://packages.devuan.org/merged/ ceres/main amd64
Packages 100 /var/lib/dpkg/status
     0.99.4-4 0
         -1 http://ftp.cz.debian.org/debian/ testing/main amd64 Packages
         -1 http://ftp.cz.debian.org/debian/ sid/main amd64 Packages
     0.99.1-really-0.9.23-2.0nosystemd1 0
        500 http://angband.pl/debian/ nosystemd/main amd64 Packages
     0.99.1-3.2 0
         -1 http://ftp.cz.debian.org/debian/ jessie/main amd64 Packages
     0.9.17-1 0
        100 http://ftp.cz.debian.org/debian/ wheezy/main amd64 Packages

> In Devuan Jessie, xfce4-power-manager is not (easily) installable
> because depends of upower (< 0.99.2) but Devuan's upower version
> number is 1:0.9.23-2+devuan1.2 while Debian Jessie 's upower version
> number is 0.99.1-3.2.

xfce4-power-manager package is not forked in Devuan. It depends on
upower (>= 0.99). I think you confused it with angband.pl
xfce4-power-manager (1.4.1-2.0nosystemd1) ?

Devuan/Debian xfce4-power-manager is satisfied by upower
1:0.9.23-2+devuan1.2 because of the epoch, and it is also the only
upower package in Devuan repositories.

IMHO xfce4-power-manager should be forked and its dependency on upower
lowered instead of adding epoch to upower. Because either upower >=
0.99 is not needed or we are already breaking xfce4-power-manager
functionality.

Petr