Issue innobackupex backup

Hello,

I try to backup percona database with innobackupex.
Unfortunatly it doesn't work
OS:debian 8.5

#innobackupex --user=root --password=xxxx --databases=xxxx /tmp/backup/
160906 11:07:45 innobackupex: Starting the backup operation

IMPORTANT: Please check that the backup run completes successfully.
           At the end of a successful backup run innobackupex
           prints "completed OK!".

160906 11:07:45 version_check Connecting to MySQL server with DSN 'dbi:mysql:;mysql_read_default_group=xtrabackup;port=3306;mysql_socket=/var/run/mysqld/mysqld.sock' as 'root' (using password: YES).
160906 11:07:45 version_check Connected to MySQL server
160906 11:07:45 version_check Executing a version check against the server...
160906 11:07:45 version_check Done.
160906 11:07:45 Connecting to MySQL server host: localhost, user: root, password: set, port: 3306, socket: /var/run/mysqld/mysqld.sock
Error: Unsupported server version: '5.7.14-7-log'. Please report a bug at https://bugs.launchpad.net/percona-xtrabackup

Have an idea please?