MyBB Community Forums

Where is that showing? That doesn't sound like anything to do with PHP, it's a client side/browser error.

The error in admin CP occurs using all browsers and many devices immediately after PHP 8,

After reverting back to PHP7.4, No errors are present

Would need a screenshot of exactly what you're seeing, "chromewebdata" doesn't sound like anything server-side. It's likely nothing to do with the ACP breaking.

Nobody else seems to be having an issue with the ACP, so either you have some other custom code running, or you may need to ask your host to help diagnose. I'm running on 8.1 and can access the ACP with no issues.

The error is Http 500 error on all browsers and all admins received this error and cannot access ACP after upgrade to PHP 8

Last time I received this error I tried to use inspect page option/source from right click menu to check for any option to help understandingwhat is this error, this was one of the options present

Revert back to PHP 7.4 fix this error and ACP is accessible again

Right, so what I'm saying is you'll need to ask your host to help debug what is causing the 500 error. The page inspector will not aid with this, that is for javascript and HTML, it will have nothing to do with a server-side error whatsoever, so the errors you're seeing there are irrelevant. A 500 error comes form the server so you cannot use browser inspector tools to debug it.

I am running 1.8.30 (and 1.8.31) on PHP 8.1 without issues, and other people seem to be able to as well, so either there are other modifications to your board, or something else going on that you will need to look at server logs to find details on.

The $modlist error Undefined variable in my image above cannot be removed and shows so many warnings once php8 is updated. The fix posted is not working and same error occurs again

The only temporary solution is remove the $modlist word manual from default template "forum bit depth 2"....till a solution is posted

You need to apply the fix mentioned above: https://github.com/mybb/mybb/commit/567f...3244e7218f

This defined the variable, it will not error if it is defined. If it is still erroring after that, then the fix has not been applied properly.

Thanks so much, $Modlist and many issues are resolved and all plugins causing ACP errors were uninstalled. I can access ACP again

The following errors are still present:

ACP: plugin updates page errors:

Warning [2] Undefined array key "codename" - Line: 222 - File: admin/modules/config/plugins.php PHP 8.0.23 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/admin/modules/config/plugins.php 222 errorHandler->error_callback
/admin/index.php 825 require

Warning [2] Undefined array key "vulnerable" - Line: 309 - File: admin/modules/config/plugins.php PHP 8.0.23 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/admin/modules/config/plugins.php 309 errorHandler->error_callback
/admin/index.php 825 require

Warning [2] Trying to access array offset on value of type null - Line: 309 - File: admin/modules/config/plugins.php PHP 8.0.23 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/admin/modules/config/plugins.php 309 errorHandler->error_callback
/admin/index.php 825 require

Warning [2] Undefined array key "vulnerable" - Line: 309 - File: admin/modules/config/plugins.php PHP 8.0.23 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/admin/modules/config/plugins.php 309 errorHandler->error_callback
/admin/index.php 825 require

Warning [2] Trying to access array offset on value of type null - Line: 309 - File: admin/modules/config/plugins.php PHP 8.0.23 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/admin/modules/config/plugins.php 309 errorHandler->error_callback
/admin/index.php 825 require

User CP errors:

Warning [2] Undefined array key "canonlyviewownthreads" - Line: 4381 - File: usercp.php PHP 8.0.23 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/usercp.php 4381 errorHandler->error_callback

Warning [2] Undefined array key "tid" - Line: 4430 - File: usercp.php PHP 8.0.23 (Linux)
File Line Function
/inc/class_error.php 153 errorHandler->error
/usercp.php 4430 errorHandler->error_callback

Notes:

Most errors are undefined array, undefined property and some are undefined variable

I have temporarily hidden these errors to check if there is any other forum problems with PHP 8 migration

Some plugins are incompatible with PHP8 and cause fatal errors in admin CP or in plugin page, I completely uninstall all these plugins

Thanks, candidate fixes for these were added to https://github.com/mybb/mybb/pull/4594

Hi,
My hosting provider let me know that PHP 7.4 will only be supported until 28.11 so I changed PHP to version 8.1 but that caused some errors so I rolled back PHP to 7.4 and upgraded MyBB from 1.8.30 to 1.8.31 hoping this would fix the problem. Unfortunately, after switching to PHP 8.1, errors still appear (see attachments). I guess the first error comes from a plugin, but I have no idea what about the rest. Can anyone help me with this problem?