Here is table with compatibility of Prestashop versions with PHP versions:
Recently, there have been several attacks caused by a security flaw in few Prestashop modules. Here is the list:
Prestashop 1.7 doesn't have option to enter API key in administration to make Google Maps working. If you want to have Google Maps in order detail, you have to edit core file manually.
PHPUnit is a testing framework for PHP, used for testing during Prestashop development. It should not be distributed with modules, but in some cases it was (ZIP archives etc.). There is known vulnerability of PHPUnit that allows allows an attacker to execute PHP code on your shop, read your database and upload or modify files - install other malware etc.
PrestaShop 1.7 introduces a new Smarty helper to generate URLs. Here are some examples
New module for product comments in 1.7.6 version shows default number of stars as 3 stars. You can simple change it as you want.
This error can occur in two cases: 1. Client wants to edit his address but click on save button several times. This creates duplicity in database and client cannot make another order due to the carriers error. 2. Client who already made order before, changes the address. Then he can't make another order.
Prestashop 1.7 has issues with blocking CSS and JS cache files from theme folder by robots.txt.
If you see this error while trying to send the contact form, one reason may be that you have latest version of contactform module, but you didn't updated your theme.