I just upgraded to the newest version 1.5.7f.
I'm using the German version (zen-cart-pro.at).

1. Various items e.g. "stats_products_lowstock" in the admin don't work and show up a simple white HTML error page and an additional warning log (see below):

HTML Code:
[11-Apr-2023 09:02:32 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function error_log() in /includes/extra_configures/enable_error_logging.php:91
Stack trace:
#0 /admin/stats_products_lowstock.php(16): zen_debug_error_handler()
#1 /admin/index.php(18): require('...')
#2 {main}
thrown in /includes/extra_configures/enable_error_logging.php on line 91
[11-Apr-2023 09:02:32 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function error_log() in /includes/extra_configures/enable_error_logging.php:104
Stack trace:
#0 [internal function]: zen_fatal_error_handler()
#1 {main}
thrown in /includes/extra_configures/enable_error_logging.php on line 104
[11-Apr-2023 09:02:32 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function error_log() in /includes/extra_configures/enable_error_logging.php:91
Stack trace:
#0 /includes/classes/db/mysql/query_factory.php(123): zen_debug_error_handler()
#1 /includes/classes/db/mysql/query_factory.php(477): queryFactory->prepare_input()
#2 /includes/classes/db/mysql/query_factory.php(511): queryFactory->getBindVarValue()
#3 /includes/functions/sessions.php(75): queryFactory->bindVars()
#4 [internal function]: _sess_write()
#5 {main}
thrown in /includes/extra_configures/enable_error_logging.php on line 91
[11-Apr-2023 09:02:32 Europe/Berlin] PHP Fatal error: Uncaught Error: Call to undefined function error_log() in /includes/extra_configures/enable_error_logging.php:91
Stack trace:
#0 [internal function]: zen_debug_error_handler()
#1 {main}
thrown in /includes/extra_configures/enable_error_logging.php on line 91
2. On a test subdomain I installed a fresh installation which also shows the following error:

  1. Installation with 8.0.27 finishes well
  2. Loading Frontend and Backend shows only white page / HTML error
  3. Switching to PHP 7.4.33 and reloading works
  4. Switching then back again to 8.0.27 and reloading also works !!! for Frontend and Backend, but with the above problems and error logs.


The maintainer of the German version says I haven't uploaded all files. But I compared the downloaded file and I unzipped the full file directly on the server via SSH.

3. Another curiosity is that the module for showing "price per unit" disappears in the Fronend when switching to PHP 7.4.33

Any help is very appreciated.

Information about my system

zc German version (zen-cart-pro.at) 1.5.7f
debian stable
Linux 5.10.0-21-amd64
PHP 8.0.27
PHP Memory Limit: 256M
Datenbank Engine: MySQL 10.5.18-MariaDB-0+deb11u1
MySQL Slow Query Log Status: Off
MySQL Modus: (None set)