Could you point how to workaround this issue when Magento is doing a readiness check?

Hi

I'm using: Magento-CE-2.2.5  I had installed it at about 01 year ago. I will look for a more recent version so.

Version 2.3 supports PHP up to 7.3:
https://devdocs.magento.com/guides/v2.3/install-gde/system-requirements-tech.html

Amazing Magento-CE-2.2.5, relatively recent, asking a so deprecated extension as mcrypt

Hi,

There are several changes from PHP 7.2, note some third party script may not be compatible too.
If you have a lot of custom code and modules you may want to check if this is compatible prior the update

You can scan and get the result using PHPCodeSniffer with  PHPCompatibility
It is a lot more easier to scan using Linux
https://www.experts-exchange.com/questions/29152482/How-to-set-and-use-PHPCodeSniffer-with-PHPCompatibility.html?anchorAnswerId=42912921#a42912921

You can also read the documentation about the changes
https://www.php.net/manual/en/migration72.php

Some errors won't be catch so you may also want to display PHP errors during your tests.

The mcrypt extension is only necessary for PHP 5 and below. It only wanted it because it didn't detect your PHP version.

But accordingly with the question's picture PHP version looks to be detected....

It knows that your version is PHP 7.2 but that wasn't the required version of PHP for Magento 2.2.

Magento 2.2 was looking SPECIFICALLY for PHP 7.0 or 7.1. Since it didn't find that, it thought you might be using an unsupported/early version and looked for mcrypt.

Hi,
You can downgrade the PHP version or update Magento and all related third party or custom script.

You have 2x choices.

1) Upgrade Magento.

2) Downgrade PHP.

Well

In the meanwhile I used a 1.9.10 Magento with PHP 7.0.31  and it runs fine.

I'm upgrading magento.

Likely upgrade path will be to upgrade Magento to latest, then upgrade PHP to latest.

This should work.

I still maintained PHP  version 7.2.6 and upgraded Magento to  Magento-CE-2.3.3-2019-09-26-03-30-45

It goes fine:

And installing....

Everything is fine:

Thank you for the help!!!

You're welcome!

PHP Tip: PHP-7.3.10.1 fixes a variety of problem which exist in PHP-7.2.6, so might be useful for you to add updating to latest PHP to your task list.

Also, PHP-7.4 will release shortly, so this might be a target also, as soon as Magento support exists for this PHP version.