Session error on php 7

Question

when I update my local host to php 7 , I have this two errors on session , I dont know its local setting on php.ini problem or my codes need update.

errors is :

[warn] #204 in lib/Zend/Session/SessionManager.php
session_write_close(): Session callback expects true/false return value

and

[warn] #204 in lib/Zend/Session/SessionManager.php
session_write_close(): Failed to write session data (user). Please verify that the current setting of session.save_path is correct (/var/lib/php/session)