Tested with Ubuntu 16.04 (Xenial) LTS and Zabbix Server 4.0 beta 1 on September 2018

Add Zabbix 4 repository (beta is version still numbered as 3.5)

echo "deb http://repo.zabbix.com/zabbix/3.5/ubuntu xenial main" | sudo tee /etc/apt/sources.list.d/zabbix4.list > /dev/null

Add the missing public key for repository with

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 082AB56BA14FE591

and update the apt package list with

apt-get update

Install the Zabbix server (if mysql has not been installed before, please note down the root password!)

apt-get install mysql-server zabbix-server-mysql zabbix-release

mysql_secure_installation

default answers (see below) are fine for a normal setup

Enter current password for root (enter for none): --> should be empty, just press Enter
Set root password? [Y/n] --> Y
Remove anonymous users? [Y/n] --> Y
Disallow root login remotely? [Y/n] -->  Y
Remove test database and access to it? [Y/n] --> Y
Reload privilege tables now? [Y/n] --> Y

$ mysql -uroot -p<password>
MariaDB [(none)]> create database zabbix character set utf8 collate utf8_bin;
MariaDB [(none)]> grant all privileges on zabbix.* to zabbix@localhost identified by '<zabbix-user-password>';
MariaDB [(none)]> flush privileges;
MariaDB [(none)]> quit;

zcat /usr/share/doc/zabbix-server-mysql/create.sql.gz | mysql -uzabbix -p zabbix enterr zabbix pwd

Now install Zabbix web frontend

apt-get install zabbix-frontend-php zabbix-get

Remember to set the right timezone for you (mine is Europe/Rome)

echo -e "<Directory \"/usr/share/zabbix\">\n   php_value date.timezone Europe/Rome\n</Directory>" | sudo tee /etc/apache2/conf-available/zabbix-local.conf
sudo a2enconf zabbix-local

and restart Apache

sudo systemctl restart apache2

http://chicago.linuxconsulting.mn.it/zabbix/setup.php

Now edit /etc/apache2/conf.d/zabbix, uncomment the date.timezone line and set the correct timezone. Mine looks like

  php_value date.timezone Europe/Rome