Not working on PHP 7

PHP message: PHP Warning: include_once(): Failed opening ‘inc/template-functions.php’ for inclusion (include_path=’.:/opt/php-7.0.0/lib/php’) in /var/www/mysite.com/wp-content/plugins/magento-wordpress-integration/mwi.php on line 532″ while reading response header from upstream, client: 94.254.144.131, server: mysite.com, request: “GET /2012/04/ciasteczka HTTP/1.1”, upstream: “fastcgi://127.0.0.1:8999”, host: “mysite.com”, referrer: “https://mysite.com/category/anycategory/”
2015/12/13 23:36:41 [error] 23622#0: *2896472 FastCGI sent in stderr: “PHP message: PHP Warning: include_once(inc/template-functions.php): failed to open stream: No such file or directory in /var/www/mysite.com/wp-content/plugins/magento-wordpress-integration/mwi.php on line 532
PHP message: PHP Warning: include_once(): Failed opening ‘inc/template-functions.php’ for inclusion (include_path=’.:/opt/php-7.0.0/lib/php’) in /var/www/mysite.com/wp-content/plugins/magento-wordpress-integration/mwi.php on line 532″ while reading response header from upstream, client: 37.47.13.228, server: mysite.com, request: “GET /?custom-css=1&csblog=1&cscache=6&csrev=74 HTTP/1.1”, upstream: “fastcgi://127.0.0.1:8999”, host: “mysite.com”, referrer: “https://mysite.com/prosby-o-modlitwe/dodaj-intencje/”
2015/12/13 23:36:49 [error] 23622#0: *2896257 FastCGI sent in stderr: “PHP message: PHP Fatal error: Mage_Core_Model_Session_Abstract::addMessage(): The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition "Mage_Core_Model_Message_Collection" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide a __autoload() function to load the class definition in /var/www/magesite.com/app/code/core/Mage/Core/Model/Session/Abstract.php on line 251” while reading response header from upstream, client: 77.253.245.203, server: mysite.com, request: “GET /categoryany HTTP/1.1”, upstream: “fastcgi://127.0.0.1:8999”, host: “mysite.com”, referrer: “https://mysite.com/”
2015/12/13 23:37:07 [error] 23622#0: *2896271 FastCGI sent in stderr: “PHP message: PHP Fatal error: Mage_Core_Model_Session_Abstract::addMessage(): The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition "Mage_Core_Model_Message_Collection" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide a __autoload() function to load the class definition in /var/www/magento.com/app/code/core/Mage/Core/Model/Session/Abstract.php on line 251” while reading response header from upstream, client: 77.253.245.203, server: mysite.com, request: “GET /categoryany/ HTTP/1.1”, upstream: “fastcgi://127.0.0.1:8999”, host: “mysite.com”, referrer: “https://mysite.com/”

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