The objective is to install Viber on Ubuntu 18.04 Bionic Beaver Linux.
Let's start by downloading the official Viber Debian package by using the wget command:
$ wget -O ~/viber.deb http://download.cdn.viber.com/cdn/desktop/Linux/viber.deb
Gayan Ramya Kumara
a good stuff. Thanks
Espeto
Thanks a lot for this solution.
victor302
I have installed viber on Ubuntu 18.04 (many thanks to Alexey Komarov for his recommendation). However, there is one more problem. The viber’s minimal size of window is too big and cannot fit the screen. The old solution using
Exec=env QT_SCALE_FACTOR=0.6 /opt/viber/Viber
does not work any more for me. I tried also QT_AUTO_SCREEN_SCALE_FACTOR variable without success. Does somebody know how to deal with that now? Thanks in advance.
frankob
This is totally NOT the way to go. Unless you don’t mind losing libcurl4 and curl along with it, causing dependency problems with every regularly maintained curl-dependent package out there (e.g. playonlinux), and generally messing up your system. Aleksey Komarov showed a much safer way to do it.
For your convenience, you can get such a modified deb here: https://mega.nz/#!B1EjlDzZ!.
This one should even work with gdebi. Of course, you don’t have to trust me, you might feel safer to do by yourself what Aleksey says. And don’t forget to remove the blank space at the last line of that control file, or it will cause an error.
The safest way is to pressure Viber to maintain a Linux version, or at least their packages. They told me they have ceased further maintenance of Viber for Linux.
Lubos Rendek Mod -> frankob
Hi Franko,
Thank you for your input! They have ceased further maintenance of Viber? Interesting, one could actually say that have not started yet! 
I have updated this article with instructions on how to install viber and ignore libcurl3 dependency. I believe this approach should be easier for an average user rather than re-building the entire package. From the article I also pointed readers to look at the comments in case someone wish to take different approach.
frankob -> Lubos Rendek
Indeed, their support for GNU/Linux was lacking and behind most of the time, anyway… But at least they did something. Now they’re telling me this: https://twitter.com/ViberHelp/status/992371791074017280
Lubos Rendek Mod → frankob
Hi Frank, thanks for the update. Well if they do not care the healthy response would be to use something else. signal.org gets my vote any time. It is mostly GPLv3 and you can find the source code on the github. What else do you need? 
frankob -> Lubos Rendek
Never used it, but I look into it, thanks!
The problem with changing IM’s, however, is always about convincing everyone else to change as well… :-/
Lubos Rendek Mod → frankob
Yes, this issue is an old never ending saga. I’ve been using signal for 3 years already, the only thing I’m missing with signal.org is Video call. But then again, they did not have native Linux desktop client up until recently and now there is one So I’m still hopeful
The bottom line is that there is no way that I’m going to make my private or otherwise phone calls using proprietary closed code and pre-compiled application like viber or whatsup.
Ivan Yarych → Lubos Rendek
It appears that’s not the way to go. After installing Viber I get this:
Bard Simpson
libcurl3 conflict with libcurl4. One should do what Aleksey Komarov says.
Pramesh Bajracharya
Jesus christ. Thank you soo much. God bless you.
Aleksey Komarov
if you want to use libcurl4, you can fix current deb file:
dpkg-deb -x viber.deb viber
dpkg-deb --control viber.deb viber/DEBIAN
Edit viber/DEBIAN/control and repace "libcurl3" with "libcurl4"
dpkg -b viber vibernew.deb
sudo dpkg -i vibernew.debNimanthaW -> Aleksey Komarov
Works great! Many thanks.
Lincoln -> Aleksey Komarov
Many thanks! That really helped!
Mourad Elgorma
i have a security probleme with this version of viber
Василий Марсель
++++++++ Good!
sudo apt install libcurl3
sudo apt install libcurl3 ~/viber.debБогдан Литвин
ne4ajb@ne4ajb-X542UQ:~$ sudo apt install libcurl3 ~/viber.deb
Reading package lists... Done
E: Unsupported file /home/ne4ajb/viber.deb given on commandlineLubos Rendek Mod -> Богдан Литвин
Check the location of your downloaded viber.deb file and make sure that you point apt to a correct location of viber.deb file otherwise you will see that error message. I have just tested this solution again it works without issues.