From 3fe6f77d248db9b945e3111ce6ecaab5d1a039ec Mon Sep 17 00:00:00 2001
From: KarlKallman <karl.kallman@epplussoftware.com>
Date: Mon, 29 Jun 2026 10:35:40 +0200
Subject: [PATCH] Allow AppVersion in OfficeProperties to be set to null.
 #2393.

---
 src/EPPlus/OfficeProperties.cs          |  8 ++++++++
 src/EPPlusTest/OfficePropertiesTests.cs | 15 +++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/src/EPPlus/OfficeProperties.cs b/src/EPPlus/OfficeProperties.cs
index 210483766f..39c01c4596 100644
--- a/src/EPPlus/OfficeProperties.cs
+++ b/src/EPPlus/OfficeProperties.cs
@@ -293,6 +293,14 @@ public string AppVersion
             get { return _extendedHelper.GetXmlNodeString(AppVersionPath); }
             set 
             {
+                if (value == null)
+                {                    
+                    if(_extendedHelper.TopNode != null)
+                    {
+                        _extendedHelper.DeleteNode(AppVersionPath);
+                    }
+                    return;
+                }                    
                 var versions = value.Split('.');
                 if(versions.Length!=2 || versions.Any(x=>!x.IsInt()))
                 {
diff --git a/src/EPPlusTest/OfficePropertiesTests.cs b/src/EPPlusTest/OfficePropertiesTests.cs
index 2ac4cc6657..17bf6342f8 100644
--- a/src/EPPlusTest/OfficePropertiesTests.cs
+++ b/src/EPPlusTest/OfficePropertiesTests.cs
@@ -1,5 +1,6 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using OfficeOpenXml;
+using OfficeOpenXml.FormulaParsing.Excel.Functions.DateAndTime;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -58,5 +59,19 @@ public void ValidateCaseInsensitiveCustomProperties_Loading()
             p.Dispose();
             p2.Dispose();
         }
+
+        [TestMethod]
+        public void AppVersion_SetToNull_RemovesNodeWithoutThrowing()
+        {
+            using var package = new ExcelPackage();
+            var props = package.Workbook.Properties;
+            var s = package.Workbook.Worksheets.Add("TestSheet");
+            s.Cells["A1"].Value = "Hej";
+            props.AppVersion = "16.0300";
+            Assert.AreEqual("16.0300", props.AppVersion);
+            
+            props.AppVersion = null;
+            Assert.IsTrue(string.IsNullOrEmpty(props.AppVersion)); 
+        }
     }
 }