HT Mega doesn’t work anymore

Since the last update, HT has stopped working. The plugin is active but when I click on “Settings” the following message appears :

“Sorry, you do not have permission to access this page.”

All blocks of our site created with HT Mega are now empty.

It seem to be our PHP version that is to low (PHP 5.6). Its too heavy for us to update our PHP to version 7.0
Is there a way to solve this problem ? Maybe you can provide us an older version of your plugin ?