From 0d1957ad2cc3fad228ef7709cfcbfb04b2927438 Mon Sep 17 00:00:00 2001
From: christof-b <mail@christof-b.de>
Date: Sat, 13 Mar 2021 12:03:05 +0100
Subject: [PATCH] Fix SpreadsheetML (xml) detection (#1917)

* Fix SpreadsheetML (xml) detection (#1916)

Replace the unrequired product signature by the
required namespace definition for XML Spreadsheet.

* Add summary to changelog (#1916)

Co-authored-by: Christof Bachmann <c.bachmann@pro54.com>
---
 CHANGELOG.md                      | 1 +
 src/PhpSpreadsheet/Reader/Xml.php | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5e273f8..2565a768 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -28,6 +28,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 - Fix for [Issue #1887](https://github.com/PHPOffice/PhpSpreadsheet/issues/1887) - Lose Track of Selected Cells After Save
 - Fixed issue with Xlsx@listWorksheetInfo not returning any data
 - Fixed invalid arguments triggering mb_substr() error in LEFT(), MID() and RIGHT() text functions. [Issue #640](https://github.com/PHPOffice/PhpSpreadsheet/issues/640)
+- Fix for [Issue #1916](https://github.com/PHPOffice/PhpSpreadsheet/issues/1916) - Invalid signature check for XML files
 
 ## 1.17.1 - 2021-03-01
 
diff --git a/src/PhpSpreadsheet/Reader/Xml.php b/src/PhpSpreadsheet/Reader/Xml.php
index b1df0ef5..a827d17a 100644
--- a/src/PhpSpreadsheet/Reader/Xml.php
+++ b/src/PhpSpreadsheet/Reader/Xml.php
@@ -116,7 +116,7 @@ class Xml extends BaseReader
 
         $signature = [
             '<?xml version="1.0"',
-            '<?mso-application progid="Excel.Sheet"?>',
+            'xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet',
         ];
 
         // Open file