One-Page Checkout [Support Thread]

[lat9]

v2.6.0 of One Page Checkout is now available for download: https://www.zen-cart.com/downloads.php?do=file&id=2095

This release contains changes associated with these GitHub issues.

[njcyx]

I need some help to upgrade 2.5.5 to 2.6.0. Zc 210. PHP 8.1

My site is running OPC 2.5.5 without any issues. Here are my attempts for the upgrade.

1. I tried to upload all the 2.6.0 factory files to my server (template folder name changed, two core files needs to be manually edited), my admin pages shows the upgrade success note which is normal. But my store front shows white screen (HTTP ERROR 500). Log is the following.

[23-Apr-2026 11:45:03 America/New_York] PHP Fatal error: Uncaught TypeError: Cannot assign null to property OnePageCheckout::$sendtoSaved of type int in /includes/functions/sessions.php:48
Stack trace:
#0 /includes/functions/sessions.php(48): session_start()
#1 /includes/init_includes/init_sessions.php(106): zen_session_start()
#2 /includes/autoload_func.php(40): require_once('/home/...')
#3 /includes/application_top.php(329): require('/home/...')
#4 /index.php(25): require('/home/...')
#5 {main}
thrown in /includes/functions/sessions.php on line 48

[23-Apr-2026 11:56:14 America/New_York] Request URI: /, IP address: 
--> PHP Fatal error: Uncaught TypeError: Cannot assign null to property OnePageCheckout::$rebuildRequired of type bool in /includes/functions/sessions.php:48
Stack trace:
#0 /includes/functions/sessions.php(48): session_start()
#1 /includes/init_includes/init_sessions.php(106): zen_session_start()
#2 /includes/autoload_func.php(40): require_once('/home/...')
#3 /includes/application_top.php(329): require('/home/...')
#4 /index.php(25): require('/home/...')
#5 {main}
thrown in /includes/functions/sessions.php on line 48. 

I uploaded my old files for 2.5.5 and it works properly.

2. I referred to the readme.html file in the zip folder to created a patch folder which only includes the files which are changed, then upload to the server. The same issue.

The funny thing is, yesterday, when I tested it in my testing site, the 2.6.0 works fine without issues. Today, I cannot make it work for both my testing site and production site...

I also noticed that there is a typo under the readme, Changes and Bugfixes, v2.6.0, "The following files were changed, added or removed"

"6. /includes/languages/english/lang.create_account/header_php_create_account_register.php"

[njcyx]

I did some further tests. Here is what I found:

Before the upgrade to 2.6.0, my site can be displayed as normal under my browser (chrome). I leave the browser tab open. After I upload all those files, my admin page can be displayed as normal, but my site (same tab) will show white screen (HTTP 500). Even I open a new browser tab, it will still show the white screen. Then I open an Incognito tab and visit my site, it can be displayed as normal with no log generated. If I open a different browser (like Firefox), I can open my site as normal.

After I downgrade my plug-in back to 2.5.5, my white screen tab can display my site as normal. This issue can be reproduced in a different computer under my network.

I have no ideas. Not sure if it is related to my browser's cookie or cache?

[lat9]

I did some further tests. Here is what I found:

Before the upgrade to 2.6.0, my site can be displayed as normal under my browser (chrome). I leave the browser tab open. After I upload all those files, my admin page can be displayed as normal, but my site (same tab) will show white screen (HTTP 500). Even I open a new browser tab, it will still show the white screen. Then I open an Incognito tab and visit my site, it can be displayed as normal with no log generated. If I open a different browser (like Firefox), I can open my site as normal.

After I downgrade my plug-in back to 2.5.5, my white screen tab can display my site as normal. This issue can be reproduced in a different computer under my network.

I have no ideas. Not sure if it is related to my browser's cookie or cache?

HTTP 500 indicates a PHP fatal error of some sort. Check the site's /logs directory and post the contents of a generated error log.

[lat9]

HTTP 500 indicates a PHP fatal error of some sort. Check the site's /logs directory and post the contents of a generated error log.

Duh, I just saw that you'd posted the log on your initial posting.

What other plugins are in use on the site, especially do you use "remember me"?

[njcyx]

Duh, I just saw that you'd posted the log on your initial posting.

What other plugins are in use on the site, especially do you use "remember me"?

Thanks for your reply.

I don't use "remember me" plug-in, but I did change/increase the session timeout. I created a php file for the following code and put it under /includes/extra_configures

<?php define('SESSION_TIMEOUT_CATALOG', 7200);

I used it in the previous zc and I kept this file when I upgrade my site to 210.

[njcyx]

Hi @lat9,

No plug-in, but I added a php file to extend the session/shopping cart expiry time. Not sure if it is related.

<?php define('SESSION_TIMEOUT_CATALOG', 7200);

This file is under /includes/extra_configures/my_ultra_long_session_timeout.php file

Reference link:

https://www.zen-cart.com/showthread....29#post1321729

Hmm, I searched the keyword "SESSION_TIMEOUT_CATALOG" and I found my same post back in 2024...

The modules I installed now are: OPC, some shipping modules, local sales tax, sales report II, monthly sales and tax summary and google recapchar.

[lat9]

Hmm, I searched the keyword "SESSION_TIMEOUT_CATALOG" and I found my same post back in 2024...

The modules I installed now are: OPC, some shipping modules, local sales tax, sales report II, monthly sales and tax summary and google recapchar.

The log you posted indicates that the issue is that data types in the saved session's OPC variable aren't compatible with those now 'required' by the v2.6.0 update.

While I'll keep my eye out for other reports of this issue, I've got no "good" solution for you other than running the following SQL queries after you've made a full backup of your database:

TRUNCATE TABLE sessions;
TRUNCATE TABLE whos_online;

[njcyx]

The log you posted indicates that the issue is that data types in the saved session's OPC variable aren't compatible with those now 'required' by the v2.6.0 update.

While I'll keep my eye out for other reports of this issue, I've got no "good" solution for you other than running the following SQL queries after you've made a full backup of your database:

TRUNCATE TABLE sessions;
TRUNCATE TABLE whos_online;

Hi @lat9, thanks. I just tried your suggestion in the testing server and it worked! After I cleaned both tables, The white screen tab can display as normal.

Regarding my database, I used zc database conversion tool (v2.0.1) to convert my database to utf8mb4_unicode_520_c from (I suspected) utf8, when I upgraded my site to zc210.

[lat9]

I still don't know what's going on with that session stuff, but I'm glad that the session-table "wipe" got you going again!