The thing is that when I tested some features, ie. Select location icon in main page, it would send me the pop up window to select the location, but with the 'page not found' message.. I rolled back to 3.7.1 and works fine now.. I don't want to elaborate the whole site, finish up and then have an annoying error like this one I just described.
In other hand, I was using PHP 5.6, I updated to PHP7 from server and it doesn't affect functionality at all.
Regards.