[Performance] Mybb Php 8.0

[JimR]

Were all the attached errors generated when running 1.8.27? Some of them suggest outdated (or modified) files.

Added some things to investigate in https://github.com/mybb/mybb/issues/4138...-872245095

running the admin cp index.php gives the following errors 



does this indicate that the $mybb object is not being created ?

If the file was executed through CLI, that may be normal.

<error>
	<script>showthread.php(1612) : eval()'d code</script>
	<line>46</line>
	<type>2</type>
	<friendly_type>Warning</friendly_type>
	<message>Undefined property: MyLanguage::$thread_modes</message>
	<back_trace>#0  errorHandler->error() called at [/showthread.php(1612) : eval()'d code:46]
#1  eval() called at [/showthread.php:1612]
</back_trace>
</error>

This language string was removed in https://github.com/mybb/mybb/pull/4351/files (template needs to be updated)

deleted error.log , copied the changed files for 18.07 to the mybb directory and re ran upgrade.php. attached is the 'new' error log

my bad added new version of the error log ..
 and cli outputs from php 7.4 & php 8.07 
php 7.4



php 8.0

as you can see php 7.4 processes the script correctly & php 8.0 does not, there are no errors written to the error log from the admin cp this is due (I guess) to the mybb object not being created  line 176 being 

$mybb->settings['errortypemedium'] = "none";

As a side note I disabled the xthreads plugin, which fails with a few errors, but for some reason mybb is still trying to load xthreads



hope this helps