Fatal error: Cannot redeclare function addslashes_gpc() (previously declared in /home/.sites/121/site5285008/web/wp-includes/formatting.php:2840) in /home/.sites/121/site5285008/web/wp-includes/deprecated.php on line 6503

Fatal error: Uncaught Error: Call to a member function set() on null in /home/.sites/121/site5285008/web/wp-includes/l10n.php:857
Stack trace:
#0 /home/.sites/121/site5285008/web/wp-includes/l10n.php(960): load_textdomain('default', '/home/.sites/12...', 'de_DE')
#1 /home/.sites/121/site5285008/web/wp-includes/class-wp-fatal-error-handler.php(49): load_default_textdomain()
#2 [internal function]: WP_Fatal_Error_Handler->handle()
#3 {main}
  thrown in /home/.sites/121/site5285008/web/wp-includes/l10n.php on line 857