Magento 1.9 – PHP 7 Support Guide

Yes, it is possible to migrate 1.9.2.2 from PHP 5.5 to PHP 7. Its not officially supported yet but Inchoo has found the solution to this.

They have developed Magento extension to make Magento compatible with PHP 7.

http://inchoo.net/magento/its-alive/

As of now from Magento 1.9.3.7 PHP 7.0 and 7.1 are officially supported. PHP 7.2 support is not yet official for both Magento 1 and 2.

Thank you

You can first add extension from github in your magento 1 app/code/local folder from here,

Magento 1 with PHP 7 Compatibility extension download from here

After that you can try to install magento 1 in your system. Now your installation should work fine.

Thanks.