# PHP Fatal error: Uncaught Error: Undefined constant "MB\_OVERLOAD\_STRING"

**URL:** https://forum.mautic.org/t/php-fatal-error-uncaught-error-undefined-constant-mb-overload-string/23015
**Category:** Mautic 3 - Install/Upgrade Support
**Created:** [March 11, 2022, 5:20pm UTC](https://forum.mautic.org/t/php-fatal-error-uncaught-error-undefined-constant-mb-overload-string/23015 "2022-03-11T17:20:43Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![nichg233333](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/nichg233333/32/6488_2.png) [@nichg233333](https://forum.mautic.org/u/nichg233333)
#### Post date: [March 11, 2022, 5:20pm UTC](https://forum.mautic.org/t/php-fatal-error-uncaught-error-undefined-constant-mb-overload-string/23015/1 "2022-03-11T17:20:43Z")

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I can’t check Mautic version now as the console -V command (and all other send commands only gives this error:

/var/www/mautic/app/console -V  
PHP Fatal error: Uncaught Error: Undefined constant “MB\_OVERLOAD\_STRING” in /var/www/mautic/vendor/joomla/string/src/phputf8/utf8.php:38  
Stack trace:  
#0 /var/www/mautic/vendor/composer/autoload\_real.php(66): require()  
#1 /var/www/mautic/vendor/composer/autoload\_real.php(56): composerRequire4c0a51d117c43ccbd70a0cd87363dc1f()  
#2 /var/www/mautic/vendor/autoload.php(7): ComposerAutoloaderInit4c0a51d117c43ccbd70a0cd87363dc1f::getLoader()  
#3 /var/www/mautic/app/autoload.php(15): require(’…’)  
#4 /var/www/mautic/app/console(19): require\_once(’…’)  
#5 {main}  
thrown in /var/www/mautic/vendor/joomla/string/src/phputf8/utf8.php on line 38

PHP version: is 7.2

I haven’t updated Mautic in a long time, but still running same configuration, same php 7.2 as before. However the php7.2 might have been update automatically.  
Any advice how I can avoid this to at least get the current mail queue sent, so that I can look into updating Mautic?

Thanks!

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<div class="post-metadata">

### Author: ![nichg233333](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/nichg233333/32/6488_2.png) [@nichg233333](https://forum.mautic.org/u/nichg233333)
#### Post date: [March 12, 2022, 7:24pm UTC](https://forum.mautic.org/t/php-fatal-error-uncaught-error-undefined-constant-mb-overload-string/23015/2 "2022-03-12T19:24:04Z")

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I found the solution. When I run the commands from CLI the PHP version is 8.1, even though I use PHP7.2 for mautic.  
Running the commands with php7.2 console -V etc doesn’t cause the error.