I've migrated my Craft project from CentOS/PHP5 to Ubuntu/PHP7 --- since then I'm seeing this message in /craft/storage/runtime/logs/phperrors.log
[14-Jun-2017 14:40:49 UTC] PHP Warning: Declaration of Craft\UserSessionService::login($username, $password, $rememberMe = false) should be compatible with CWebUser::login($identity, $duration = 0) in /home/hidden/craft/app/services/UserSessionService.php on line 17
[14-Jun-2017 14:40:49 UTC] PHP Warning: Declaration of Craft\UserSessionService::afterLogin() should be compatible with CWebUser::afterLogin($fromCookie) in /home/hidden/craft/app/services/UserSessionService.php on line 17
[14-Jun-2017 15:50:53 UTC] PHP Warning: Declaration of Craft\UserSessionService::login($username, $password, $rememberMe = false) should be compatible with CWebUser::login($identity, $duration = 0) in /home/hidden/craft/app/services/UserSessionService.php on line 17
[14-Jun-2017 15:50:53 UTC] PHP Warning: Declaration of Craft\UserSessionService::afterLogin() should be compatible with CWebUser::afterLogin($fromCookie) in /home/hidden/craft/app/services/UserSessionService.php on line 17
[14-Jun-2017 16:03:04 UTC] PHP Warning: Declaration of Craft\UserSessionService::login($username, $password, $rememberMe = false) should be compatible with CWebUser::login($identity, $duration = 0) in /home/hidden/craft/app/services/UserSessionService.php on line 17
[14-Jun-2017 16:03:04 UTC] PHP Warning: Declaration of Craft\UserSessionService::afterLogin() should be compatible with CWebUser::afterLogin($fromCookie) in /home/hidden/craft/app/services/UserSessionService.php on line 17
Any Help?