Fatal error: PHP error in file /mnt/web113/b1/41/5530641/htdocs/forum/lib/page/IrcChatPage.class.php (38): Function ereg_replace() is deprecated

Information:

error message: PHP error in file /mnt/web113/b1/41/5530641/htdocs/forum/lib/page/IrcChatPage.class.php (38): Function ereg_replace() is deprecated
error code: 0
file: /mnt/web113/b1/41/5530641/htdocs/forum/wcf/lib/system/WCF.class.php (255)
php version: 5.3.29
wcf version: 1.0.11 pl 3 (Horizon)
date: Mon, 25 Sep 2017 09:39:13 +0000
request: /index.php?page=IrcChat&s=c01a5b9fa018516c953ca0f0b7ab2c9fa30cd0f6
referer:

Stacktrace:

#0 [internal function]: WCF::handleError(8192, 'Function ereg_r...', '/mnt/web113/b1/...', 38, Array)
#1 /mnt/web113/b1/41/5530641/htdocs/forum/lib/page/IrcChatPage.class.php(38): ereg_replace()
#2 /mnt/web113/b1/41/5530641/htdocs/forum/wcf/lib/page/AbstractPage.class.php(36): IrcChatPage->show()
#3 /mnt/web113/b1/41/5530641/htdocs/forum/wcf/lib/util/RequestHandler.class.php(63): AbstractPage->__construct()
#4 /mnt/web113/b1/41/5530641/htdocs/forum/wcf/lib/util/RequestHandler.class.php(91): RequestHandler->__construct('IrcChat', Array, 'page')
#5 /mnt/web113/b1/41/5530641/htdocs/forum/index.php(8): RequestHandler::handle(Array)
#6 {main}