Title: php error mb_convert_case
Last modified: May 13, 2021

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# php error mb_convert_case

 *  Resolved [smartwebcanada](https://wordpress.org/support/users/smartwebcanada/)
 * (@smartwebcanada)
 * [5 years, 2 months ago](https://wordpress.org/support/topic/php-error-mb_convert_case/)
 * Hello,
    After upgrading to php 7.4 we getting this error. PHP Fatal error: Uncaught
   Error: Call to undefined function Nextend\Framework\FastImageSize\mb_convert_case()
 * Is there a need to be enable on our side?

Viewing 2 replies - 1 through 2 (of 2 total)

 *  [Ramona](https://wordpress.org/support/users/nextend_ramona/)
 * (@nextend_ramona)
 * [5 years, 2 months ago](https://wordpress.org/support/topic/php-error-mb_convert_case/#post-14458401)
 * Hi [@smartwebcanada](https://wordpress.org/support/users/smartwebcanada/)
 * I’m sorry for the delayed reply, for some reason we didn’t get notification about
   your topic.
 * Probably the “mbstring” PHP extension installed on your site:
    [https://www.php.net/manual/en/mbstring.installation.php](https://www.php.net/manual/en/mbstring.installation.php)
   Contact your host and ask them to install and enable this PHP extension.
 * Also, this mb_convert_case() function is only used since 3.5, which is not available
   for WordPress free yet. This suggest you’re using the Pro version, so please 
   contact us here for support:
    [https://smartslider3.com/contact-us/support/](https://smartslider3.com/contact-us/support/)
 * Also, we’ll remove this code from the upcoming version, which we plan to release
   tomorrow. If you contact us at our support channel, I can send the new installer
   before its released.
 * As per forum rules, commercial products are [not supported in these forums](https://wordpress.org/support/guidelines/#do-not-post-about-commercial-products).
   So we can’t help pro customers here.
 *  Thread Starter [smartwebcanada](https://wordpress.org/support/users/smartwebcanada/)
 * (@smartwebcanada)
 * [5 years, 2 months ago](https://wordpress.org/support/topic/php-error-mb_convert_case/#post-14458738)
 * Hello,
    Thank you…So, is that the 3.5.06? I updated today and upgraded the version
   of php to 7.4 but still didnt work… Will contact you on the support site and 
   ask…
 * Thank you

Viewing 2 replies - 1 through 2 (of 2 total)

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## Tags

 * [php](https://wordpress.org/support/topic-tag/php/)
 * [smart-slider](https://wordpress.org/support/topic-tag/smart-slider/)

 * 2 replies
 * 2 participants
 * Last reply from: [smartwebcanada](https://wordpress.org/support/users/smartwebcanada/)
 * Last activity: [5 years, 2 months ago](https://wordpress.org/support/topic/php-error-mb_convert_case/#post-14458738)
 * Status: resolved