Do you use a Linux server or a Windows server?
If you do use a Linux server type in a terminal : php -v
If you are not using PHP 7 in my opinion you may ignore these messages.
If you are using PHP 7 you should not have come as far as you obviously are.
If you use PHP 7, for the mysql-error see "http://usysto.net/php-7-mit-alten-mysql-funktionen_325
Again, if you use PHP 7, for the preg-replace error see "http://php.net/manual/de/migration55.deprecated.php
If you are using a Windows server in my opinion it should be similar.
I myself use a Linux server (Ubuntu 16.04.01 with Apache/2.4.18, feng office 126.96.36.199, PHP 7.0.13, mysql Ver 14.14 Distrib 5.7.17) and had to modify until now 256 files of 3048 php-files and one *.inc file for porting to PHP 7 and now at least feng office 188.8.131.52 runs smoothly. So good luck!