diff --git a/src/OrchardCore.Modules/OrchardCore.ContentTypes/ViewModels/EditPartViewModel.cs b/src/OrchardCore.Modules/OrchardCore.ContentTypes/ViewModels/EditPartViewModel.cs
index d5e55fac293..e6a00cc628b 100644
--- a/src/OrchardCore.Modules/OrchardCore.ContentTypes/ViewModels/EditPartViewModel.cs
+++ b/src/OrchardCore.Modules/OrchardCore.ContentTypes/ViewModels/EditPartViewModel.cs
@@ -2,7 +2,7 @@
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using OrchardCore.ContentManagement.Metadata.Models;
 using OrchardCore.ContentManagement.Metadata.Settings;
-using OrchardCore.Mvc.Utilities;
+using OrchardCore.ContentManagement.Utilities;
 
 namespace OrchardCore.ContentTypes.ViewModels;
 
@@ -26,7 +26,7 @@ public EditPartViewModel(ContentPartDefinition contentPartDefinition)
     [Required]
     public string DisplayName
     {
-        get { return !string.IsNullOrWhiteSpace(_displayName) ? _displayName : Name.TrimEnd("Part").CamelFriendly(); }
+        get { return !string.IsNullOrWhiteSpace(_displayName) ? _displayName : Name.TrimEndString("Part").CamelFriendly(); }
         set { _displayName = value; }
     }
 
diff --git a/src/OrchardCore.Modules/OrchardCore.Demo/Controllers/ContentApiController.cs b/src/OrchardCore.Modules/OrchardCore.Demo/Controllers/ContentApiController.cs
index 02c07f60fca..7ec39605e1c 100644
--- a/src/OrchardCore.Modules/OrchardCore.Demo/Controllers/ContentApiController.cs
+++ b/src/OrchardCore.Modules/OrchardCore.Demo/Controllers/ContentApiController.cs
@@ -55,7 +55,6 @@ public async Task<IActionResult> GetAuthorizedById(string id)
     }
 
     [HttpPost]
-    [Authorize]
     public async Task<IActionResult> AddContent(ContentItem contentItem)
     {
         if (!await _authorizationService.AuthorizeAsync(User, Permissions.DemoAPIAccess))
diff --git a/src/OrchardCore.Modules/OrchardCore.Menu/GraphQL/MenuItemContentTypeBuilder.cs b/src/OrchardCore.Modules/OrchardCore.Menu/GraphQL/MenuItemContentTypeBuilder.cs
index 6b1b8858d31..f384327ec17 100644
--- a/src/OrchardCore.Modules/OrchardCore.Menu/GraphQL/MenuItemContentTypeBuilder.cs
+++ b/src/OrchardCore.Modules/OrchardCore.Menu/GraphQL/MenuItemContentTypeBuilder.cs
@@ -1,7 +1,7 @@
+using System;
 using GraphQL.Resolvers;
 using GraphQL.Types;
 using OrchardCore.ContentManagement;
-using OrchardCore.ContentManagement.GraphQL;
 using OrchardCore.ContentManagement.GraphQL.Queries.Types;
 using OrchardCore.ContentManagement.Metadata.Models;
 using OrchardCore.Menu.Models;
diff --git a/src/OrchardCore.Modules/OrchardCore.Menu/GraphQL/MenuItemsListQueryObjectType.cs b/src/OrchardCore.Modules/OrchardCore.Menu/GraphQL/MenuItemsListQueryObjectType.cs
index 24308cf57ee..15627321436 100644
--- a/src/OrchardCore.Modules/OrchardCore.Menu/GraphQL/MenuItemsListQueryObjectType.cs
+++ b/src/OrchardCore.Modules/OrchardCore.Menu/GraphQL/MenuItemsListQueryObjectType.cs
@@ -10,7 +10,7 @@ public MenuItemsListQueryObjectType()
         Name = "MenuItemsListPart";
 
         Field<ListGraphType<MenuItemInterface>>("menuItems")
-           .Description("The menu items.")
+            .Description("The menu items.")
             .Resolve(context => context.Source.MenuItems);
 
     }
diff --git a/src/OrchardCore/OrchardCore.Abstractions/Json/Serialization/DateTimeJsonConverter.cs b/src/OrchardCore/OrchardCore.Abstractions/Json/Serialization/DateTimeJsonConverter.cs
index bf2415e6979..8d694aef46f 100644
--- a/src/OrchardCore/OrchardCore.Abstractions/Json/Serialization/DateTimeJsonConverter.cs
+++ b/src/OrchardCore/OrchardCore.Abstractions/Json/Serialization/DateTimeJsonConverter.cs
@@ -18,7 +18,7 @@ public override DateTime Read(ref Utf8JsonReader reader, Type typeToConvert, Jso
 
         if (!reader.TryGetDateTime(out var value))
         {
-            var stringValue = reader.GetString(); 
+            var stringValue = reader.GetString();
             if (DateTime.TryParse(stringValue, out value))
             {
                 return value;
diff --git a/src/OrchardCore/OrchardCore.ContentManagement.Abstractions/Metadata/Settings/ContentPartSettingsExtensions.cs b/src/OrchardCore/OrchardCore.ContentManagement.Abstractions/Metadata/Settings/ContentPartSettingsExtensions.cs
index 46bd01e3935..ca0bf7484c8 100644
--- a/src/OrchardCore/OrchardCore.ContentManagement.Abstractions/Metadata/Settings/ContentPartSettingsExtensions.cs
+++ b/src/OrchardCore/OrchardCore.ContentManagement.Abstractions/Metadata/Settings/ContentPartSettingsExtensions.cs
@@ -1,4 +1,3 @@
-using System;
 using OrchardCore.ContentManagement.Metadata.Builders;
 using OrchardCore.ContentManagement.Metadata.Models;
 using OrchardCore.ContentManagement.Utilities;
@@ -58,7 +57,7 @@ public static string DisplayName(this ContentPartDefinition part)
 
         if (string.IsNullOrEmpty(displayName))
         {
-            displayName = part.Name.TrimEnd("Part");
+            displayName = part.Name.TrimEndString("Part");
         }
 
         return displayName;
diff --git a/src/OrchardCore/OrchardCore.ContentManagement.Abstractions/Utilities/StringExtensions.cs b/src/OrchardCore/OrchardCore.ContentManagement.Abstractions/Utilities/StringExtensions.cs
index 2fd37ec8de2..9ba29c21a7b 100644
--- a/src/OrchardCore/OrchardCore.ContentManagement.Abstractions/Utilities/StringExtensions.cs
+++ b/src/OrchardCore/OrchardCore.ContentManagement.Abstractions/Utilities/StringExtensions.cs
@@ -345,6 +345,8 @@ public static string ReplaceAll(this string original, IDictionary<string, string
         return Regex.Replace(original, pattern, match => replacements[match.Value]);
     }
 
+#if NET8_0
+    [Obsolete("Don't use 'TrimEnd' as this has a different behavior in .NET 9.0. Use 'OrchardCore.ContentManagement.Utilities.TrimEndString' instead.")]
     public static string TrimEnd(this string value, string trim = "")
     {
         if (value == null)
@@ -356,6 +358,19 @@ public static string TrimEnd(this string value, string trim = "")
             ? value[..^trim.Length]
             : value;
     }
+#endif
+
+    public static string TrimEndString(this string value, string suffix)
+    {
+        if (string.IsNullOrWhiteSpace(value))
+        {
+            return value;
+        }
+
+        return value.EndsWith(suffix, StringComparison.Ordinal)
+            ? value[..^suffix.Length]
+            : value;
+    }
 
     public static string ReplaceLastOccurrence(this string source, string searchedValue, string replacedValue)
     {
diff --git a/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Extensions/StringExtensions.cs b/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Extensions/StringExtensions.cs
index f9b93aead1d..c226eadf506 100644
--- a/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Extensions/StringExtensions.cs
+++ b/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Extensions/StringExtensions.cs
@@ -1,13 +1,12 @@
-using System;
 using GraphQL;
 using OrchardCore.ContentManagement.Utilities;
 
-namespace OrchardCore.ContentManagement.GraphQL;
+namespace System;
 
 public static class StringExtensions
 {
     public static string ToFieldName(this string name)
     {
-        return name.TrimEnd("Part").ToCamelCase();
+        return name.TrimEndString("Part").ToCamelCase();
     }
 }
diff --git a/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/DynamicContentFieldsIndexAliasProvider.cs b/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/DynamicContentFieldsIndexAliasProvider.cs
index 6f5aaec157e..d6d652d2089 100644
--- a/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/DynamicContentFieldsIndexAliasProvider.cs
+++ b/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/DynamicContentFieldsIndexAliasProvider.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
diff --git a/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/DynamicContentTypeBuilder.cs b/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/DynamicContentTypeBuilder.cs
index d076a3683c1..73f85b2e256 100644
--- a/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/DynamicContentTypeBuilder.cs
+++ b/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/DynamicContentTypeBuilder.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using GraphQL.Resolvers;
diff --git a/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/TypedContentTypeBuilder.cs b/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/TypedContentTypeBuilder.cs
index a34af732813..02569f1789a 100644
--- a/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/TypedContentTypeBuilder.cs
+++ b/src/OrchardCore/OrchardCore.ContentManagement.GraphQL/Queries/Types/TypedContentTypeBuilder.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using GraphQL;
 using GraphQL.Resolvers;
diff --git a/src/OrchardCore/OrchardCore.DisplayManagement.Liquid/Tags/ZoneTag.cs b/src/OrchardCore/OrchardCore.DisplayManagement.Liquid/Tags/ZoneTag.cs
index 59de447a452..796c7190bb4 100644
--- a/src/OrchardCore/OrchardCore.DisplayManagement.Liquid/Tags/ZoneTag.cs
+++ b/src/OrchardCore/OrchardCore.DisplayManagement.Liquid/Tags/ZoneTag.cs
@@ -17,7 +17,7 @@ public class ZoneTag
     public static async ValueTask<Completion> WriteToAsync(
         IReadOnlyList<FilterArgument> argumentsList,
         IReadOnlyList<Statement> statements,
-        TextWriter _,        
+        TextWriter _,
         TextEncoder encoder,
         TemplateContext context)
     {
diff --git a/src/OrchardCore/OrchardCore.Mvc.Core/Utilities/StringExtensions.cs b/src/OrchardCore/OrchardCore.Mvc.Core/Utilities/StringExtensions.cs
index 5325d08a63b..647398de87f 100644
--- a/src/OrchardCore/OrchardCore.Mvc.Core/Utilities/StringExtensions.cs
+++ b/src/OrchardCore/OrchardCore.Mvc.Core/Utilities/StringExtensions.cs
@@ -402,6 +402,8 @@ public static string ReplaceAll(this string original, IDictionary<string, string
         return Regex.Replace(original, pattern, match => replacements[match.Value]);
     }
 
+#if NET8_0
+    [Obsolete("Don't use 'TrimEnd' as this has a different behavior in .NET 9.0. Use 'OrchardCore.ContentManagement.Utilities.TrimEndString' instead.")]
     public static string TrimEnd(this string rough, string trim = "")
     {
         if (rough == null)
@@ -413,6 +415,7 @@ public static string TrimEnd(this string rough, string trim = "")
                    ? rough[..^trim.Length]
                    : rough;
     }
+#endif
 
     public static string ReplaceLastOccurrence(this string source, string find, string replace)
     {
diff --git a/src/docs/releases/2.0.0.md b/src/docs/releases/2.0.0.md
index 86a243bf77f..3cf714f41ac 100644
--- a/src/docs/releases/2.0.0.md
+++ b/src/docs/releases/2.0.0.md
@@ -739,3 +739,9 @@ Many type commonly used by modules can be `sealed`, which improves runtime perfo
 ### Workflow Trimming
 
 The Workflows module now has a `Trimming` feature to automatically clean up old workflow instances. See [the corresponding documentation](../reference/modules/Workflows/README.md#trimming) for details.
+
+### Obsoleting `TrimEnd`
+
+The methods `public static string TrimEnd(this string value, string trim = "")` from `OrchardCore.Mvc.Utilities` and `OrchardCore.ContentManagement.Utilities` are being obsoleted and replaced by 
+`OrchardCore.ContentManagement.Utilities.TrimEndString(this string value, string suffix)`. This was done to prepare the code base for the next .NET 9.0 release which has a conflicting method 
+with a different behavior.