Fatal error: Uncaught Error: Call to undefined function mcrypt_module_open()

[meneel]

I have upgraded my PHP version 5.6 to 7.4, my current magento version is 1.9.

After upgrading php version I am getting this error "Fatal error: Uncaught Error: Call to undefined function mcrypt_module_open()  lib/Varien/Crypt/Mcrypt.php on line 74". How to resolve this issue? This is live site. Please help.

[Gaurav_Jain02 · Accepted solution]

Hello @meneel 

Magento 1.9 is not compatible with php 7.4.
You can max use PHP 7.0 but you may need to install this compatibility extension

https://github.com/Inchoo/Inchoo_PHP7

We recommend to upgrade your Magento version to 2.4 which supports php7.4 and have all the latest features and security,