Need help installing Mono framework on Raspberry Pi3 running OpenHab2 (openhabian) - linux

Question

I'm trying to install Mono on a Raspberry Pi3 that runs OpenHab2 (openhabian).
Unfortunately I'm not familiar with Linux and need some help please.
I followed Mono for RPI instructions from here and unfortunately got into some dependencies-related problems that I don’t know how to solve.
I searched online and found some advice to first install ‘mono-vbnc’ and ‘mono-complete’ :
sudo apt-get install mono-vbnc mono-complete
Unfortunately it also gives some errors:
openhabian#openHAB2:~$ sudo apt-get install mono-vbnc mono-complete
[sudo] password for openhabian: Reading package lists… Done Building
dependency tree Reading state information… Done Some packages could
not be installed. This may mean that you have requested an impossible
situation or if you are using the unstable distribution that some
required packages have not yet been created or been moved out of
Incoming. The following information may help to resolve the situation:
The following packages have unmet dependencies: mono-complete :
Depends: mono-runtime (= 5.4.0.201-0xamarin10+raspbian9b1) but it is
not going to be installed Depends: mono-runtime-sgen (=
5.4.0.201-0xamarin10+raspbian9b1) but it is not going to be installed Depends: mono-utils (= 5.4.0.201-0xamarin10+raspbian9b1) but it is not
going to be installed Depends: mono-devel (=
5.4.0.201-0xamarin10+raspbian9b1) but it is not going to be installed Depends: mono-mcs (= 5.4.0.201-0xamarin10+raspbian9b1) but it is not
going to be installed Depends: mono-roslyn (=
5.4.0.201-0xamarin10+raspbian9b1) but it is not going to be installed Depends: mono-csharp-shell (= 5.4.0.201-0xamarin10+raspbian9b1) but it
is not going to be installed Depends: mono-4.0-gac (=
5.4.0.201-0xamarin10+raspbian9b1) but it is not going to be installed Depends: mono-4.0-service (= 5.4.0.201-0xamarin10+raspbian9b1) but it
is not going to be installed Depends: monodoc-base (=
5.4.0.201-0xamarin10+raspbian9b1) but it is not going to be installed Depends: monodoc-manual (= 5.4.0.201-0xamarin10+raspbian9b1) but it is
not going to be installed Depends: libmono-cil-dev (=
5.4.0.201-0xamarin10+raspbian9b1) but it is not going to be installed Depends: ca-certificates-mono (= 5.4.0.201-0xamarin10+raspbian9b1) but
it is not going to be installed mono-vbnc : Depends:
libmono-microsoft-visualbasic10.0-cil (= 4.6-0xamarin10+raspbian9b1)
but it is not going to be installed Depends:
libmono-accessibility4.0-cil but it is not going to be installed
Depends: libmono-system-configuration4.0-cil but it is not going to be
installed Depends: libmono-system-data4.0-cil but it is not going to
be installed Depends: libmono-system-design4.0-cil but it is not going
to be installed Depends: libmono-system4.0-cil (>= 4.0.0~alpha1) but
it is not going to be installed Depends:
libmono-system-drawing-design4.0-cil but it is not going to be
installed Depends: libmono-system-drawing4.0-cil but it is not going
to be installed Depends: libmono-system-web4.0-cil but it is not going
to be installed Depends: libmono-system-web-services4.0-cil but it is
not going to be installed Depends: libmono-system-windows-forms4.0-cil
but it is not going to be installed Depends: libmono-system-xml4.0-cil
but it is not going to be installed Depends: mono-runtime (>= 3.0~)
but it is not going to be installed Depends: libmono-cecil-vb0.9-cil
(>= 2.99) but it is not going to be installed Depends:
libmono-corlib4.5-cil (>= 4.0.0~alpha1) but it is not going to be
installed Depends: libmono-system-core4.0-cil (>= 4.0.0~alpha1) but it
is not going to be installed E: Unable to correct problems, you have
held broken packages. Could someone please help me install ‘mono
framework’ on RPi3 running openhabian?
Thanks in advance!
-Mark
P.S.: Just in case.
################# openHAB2 ######################################## 7.05.170509
###############################################################################
## Ip = 192.168.1.60
## Release = Raspbian GNU/Linux 8 (jessie)
## Kernel = Linux 4.9.35-v7+
## Platform = Raspberry Pi 3 Model B Rev 1.2
## Uptime = 0 day(s). 11:35:3
## CPU Usage = 1.51 % avg over 4 cpu(s) (4 core(s) x 1 socket(s))
## CPU Load = 1m: 0.00, 5m: 0.00, 15m: 0.00
## Memory = Free: 0.40GB (43%), Used: 0.54GB (57%), Total: 0.94GB
## Swap = Free: 0.09GB (100%), Used: 0.00GB (0%), Total: 0.09GB
## Root = Free: 26.08GB (92%), Used: 2.00GB (8%), Total: 29.31GB
## Updates = 0 apt-get updates available.
## Sessions = 1 sessions
## Processes = 131 running processes of 32768 maximum processes
###############################################################################
openHAB 2.1.0-1 (Release Build)