Installation Error with version 3.5.17

[adb34]

Checked this problem with Microsoft Edge, Firefox and Chrome web browsers and I get the same error in both the main page and back office.

I have installed v3.5.17 via 1&1 control panel, as this is their latest update with a date stamp of 20.09.16, and I am getting errors on the home screen of my website.

Fatal error: Uncaught exception Error with message Call to undefined function Contao\Database\mysql_connect() thrown in system/modules/core/library/Contao/Database/Mysql.php on line 47
#0 system/modules/core/library/Contao/Database.php(81): Contao\Database\Mysql->connect()
#1 system/modules/core/library/Contao/Database.php(165): Contao\Database->__construct(Array)
#2 [internal function]: Contao\Database::getInstance()
#3 system/modules/core/library/Contao/System.php(140): call_user_func(Array)
#4 system/modules/core/library/Contao/User.php(158): Contao\System->import('Database')
#5 system/modules/core/classes/FrontendUser.php(62): Contao\User->__construct()
#6 system/modules/core/library/Contao/User.php(220): Contao\FrontendUser->__construct()
#7 [internal function]: Contao\User::getInstance()
#8 system/modules/core/library/Contao/System.php(140): call_user_func(Array)
#9 system/modules/core/controllers/FrontendIndex.php(31): Contao\System->import('FrontendUser', 'User')
#10 index.php(19): Contao\FrontendIndex->__construct()
#11 {main}

Would it be best to over write this installation with up-to-date version, or is there something fundamentally wrong with the initial load?
My site address if you want to take a look.

[Spooky]

Edit your /system/config/localconfig.php and change this line

$GLOBALS['TL_CONFIG']['dbDriver'] = 'MySQL'; 

to

$GLOBALS['TL_CONFIG']['dbDriver'] = 'MySQLi'; 

[adb34]

Edit your /system/config/localconfig.php and change this line

$GLOBALS['TL_CONFIG']['dbDriver'] = 'MySQL'; 

to

$GLOBALS['TL_CONFIG']['dbDriver'] = 'MySQLi'; 

I will give it a go and get back with the answer

[adb34]

I will give it a go and get back with the answer

e right
My site is now showing the 'we'll be right back' in the middle of the screen.

Thank you for the info.

[Spooky]

That's the screen for the maintenance mode. You can disable the maintenance mode in the backend or directly in the /system/config/localconfig.php

[adb34]

That's the screen for the maintenance mode. You can disable the maintenance mode in the backend or directly in the /system/config/localconfig.php

Yes I have got passed that. Thanks for the info. I am now looking at an update before I do anything else