What has changed
The previous Tigervnc versions had a wrapper script called vncserver which could be run as a user manually to start Xvnc process. The usage was quite simple as you just run

$ vncserver :x [vncserver options] [Xvnc options]
and that was it. While this was working just fine, there were issues when users wanted to start a Tigervnc server using systemd. For these reasons things were completely changed and there is now a new way how this all is supposed to work.

# How to start Tigervnc server  

Add a user mapping
With this you can map a user to a particular port. The mapping should be done in /etc/tigervnc/vncserver.users configuration file. It should be pretty straightforward once you open the file as there are some examples, but basically the mapping is in form

:x=user
For example you can have

:1=test
:2=vncuser
Configure Xvnc options
To configure Xvnc parameters, you need to go to the same directory where you did the user mapping and open vncserver-config-defaults configuration file. This file is for the default Xvnc configuration and will be applied to every user unless any of the following applies: The user has its own configuration in $HOME/.vnc/config The same option with different value is configured in   vncserver-config-mandatory configuration file, which replaces the default   configuration and has even a higher priority than the per-user configuration.   This option is for system administrators when they want to force particular   Xvnc options.

Format of the configuration file is also quite simple as the configuration is in form of

option=value
option
for example

session=gnome
securitytypes=vncauth,tlsvnc
desktop=sandbox
geometry=2000x1200
localhost
alwaysshared
Note:
There is one important option you need to set and that option is the session you want to start. E.g when you want to start GNOME desktop, then you have to use

session=gnome
which should match the name of a session desktop file from /usr/share/xsessions directory.

Set VNC password
You need to set a password for each user in order to be able to start the Tigervnc server. In order to create a password, you just run

$ vncpasswd
as the user you will be starting the server for.

Note:
If you were using Tigervnc before for your user and you already created a password, then you will have to make sure the $HOME/.vnc folder created by vncpasswd will have the correct SELinux context. You either can delete this folder and recreate it again by creating the password one more time, or alternatively you can run

$ restorecon -RFv /home/<USER>/.vnc
Start the Tigervnc server
Finally you can start the server using systemd service. To do so just run

$ systemctl start vncserver@:x
as root or

$ sudo systemctl start vncserver@:x
as a regular user in case it has permissions to run sudo. Don't forget to replace the :x by the actual number you configured in the user mapping file. Following our example by running

$ systemctl start vncserver@:1
you will start a Tigervnc server for user test with a GNOME session.

Note:
If you were previously using Tigervnc and you were used to start it using systemd then you will need to remove previous systemd configuration files, those you most likely copied to /etc/systemd/system/vncserver@.service, otherwise this service file will be preferred over the new one installed with latest Tigervnc.

Limitations
You will not be able to start a Tigervnc server for a user who is already logged into a graphical session. Avoid running the server as the root user as it's not a safe thing to do. While running the server as the root should work in general, it's not recommended to do so and there might be some things which are not working properly.