Steps to reproduce the issue

• Install 4.0-dev with testing sample data.
• Open front end or back end after installation.

Warning: Declaration of JCacheControllerCallback::get(callable $callback, $args = Array, $id = false, $wrkarounds = false, $woptions = Array) should be compatible with JCacheController::get($id, $group = NULL) in /libraries/joomla/cache/controller/callback.php on line 174

System Information

PHP Built On Linux dd1620 3.13.0-96-generic #143-Ubuntu SMP Mon Aug 29 20:15:20 UTC 2016 x86_64
Database Version 5.5.52-nmm1-log
Database Collation utf8_general_ci
Database Connection Collation utf8mb4_general_ci
PHP Version 7.0.10-nmm1
Web Server Apache
WebServer to PHP Interface fpm-fcgi
Joomla! Version Joomla! 4.0.0-dev Development [ Noether ] 4-July-2016 15:28 GMT
User Agent Mozilla/5.0 (Windows NT 10.0; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0