diff --git a/src/Umbraco.Core/Configuration/Models/RuntimeSettings.cs b/src/Umbraco.Core/Configuration/Models/RuntimeSettings.cs
index a461815897..e492515906 100644
--- a/src/Umbraco.Core/Configuration/Models/RuntimeSettings.cs
+++ b/src/Umbraco.Core/Configuration/Models/RuntimeSettings.cs
@@ -21,6 +21,7 @@ public class RuntimeSettings
///
/// Gets or sets a value for the maximum query string length.
///
+ [Obsolete("No longer used and will be removed in Umbraco 16.")]
public int? MaxQueryStringLength { get; set; }
///