PHP7 will be released soon and many of us would like to get more knowledge about new version. Also it would be good to start prepare your PHP-based applications to work with the new version.
Davey Shafik wrote an e-book “Upgrading to PHP 7” which is available for free. You can download it here in following formats: ePub, Mobi, PDF.
PHP 7 Upgrade – free e-book