My site has been working fine since the last 2 3 months, but now it shows a 500 Server error message. Then I saw a file error.logthat says that
PHP Fatal error: function call undefined utf8_substr () in public_html / catalog / model / tool / image.php on line 11
And the code in this place:
$new_image = 'cache/' . utf8_substr($filename, 0, utf8_strrpos($filename, '.')) . '-' . $width . 'x' . $height . '.' . $extension;
Then I thought it was due to the cache, and then I cleared the cache and still get the same error message. I was looking for a solution for google, and I found several solutions, such as Clearing cachecheck if there is / t 23> or utf8.php, but the file is in the right place. This is an env production and the site has not been working since the last two days.
Please tell me the solution to this problem.
I am running Opencart version 2.0.3.1
Thanks in advance