Issues with upgrade from 1.4.22 to 1.5.48

[fcv]

Hello all! I have used the Coppermine gallery version 1.4.22 for a long time, pretty much since it was available on my hosting account. It's been a few years since I have uploaded any pictures to it, so I haven't accessed it at all. A few a months ago, I tried accessing and all I got was a blank page. No error messages whatsoever. I contacted chat support of my hosting account provider and I was told that there is no issues on the server and that I should update to the newest version of the Coppermine gallery.

Last night I uploaded all the files from the 1.5.48 package to my gallery folder, except for anycontent.php and albums folder, as it is indicated on the upgrade instructions. I ran the update.php and I see this message come up...

Fatal error: Uncaught Error: Call to undefined function mysql_connect() in /home1/firmaone/public_html/galerija/include/functions.inc.php:183 Stack trace: #0 /home1/firmaone/public_html/galerija/include/init.inc.php(171): cpg_db_connect() #1 /home1/firmaone/public_html/galerija/update.php(27): include_once('/home1/firmaone...') #2 {main} thrown in /home1/firmaone/public_html/galerija/include/functions.inc.php on line 183

The link to my gallery is http://www.firma1989.com/galerija/update.php

Can someone help and explain how to fix this? Thanks in advance.