diff --git a/src/libraries/Microsoft.PowerFx.Core/Entities/External/TableDelegationInfo.cs b/src/libraries/Microsoft.PowerFx.Core/Entities/External/TableDelegationInfo.cs
index bfc62c3358..08ee5073d5 100644
--- a/src/libraries/Microsoft.PowerFx.Core/Entities/External/TableDelegationInfo.cs
+++ b/src/libraries/Microsoft.PowerFx.Core/Entities/External/TableDelegationInfo.cs
@@ -23,7 +23,8 @@ public abstract class TableDelegationInfo
         // Used to indicate whether this table has selectable columns
         public SelectionRestrictions SelectionRestriction { get; init; }
 
-        public SummarizeRestrictions SummarizeRestriction { get; init; }
+        [Obsolete("preview")]
+        public SummarizeCapabilities SummarizeCapabilities { get; init; }
 
         // Defines ungroupable columns
         public GroupRestrictions GroupRestriction { get; init; }
@@ -268,20 +269,25 @@ public SelectionRestrictions()
         }
     }
 
-    public sealed class SummarizeRestrictions
+    [Obsolete("preview")]
+    public class SummarizeCapabilities
     {
-        /// <summary>
-        /// List of properties that can not be summarized.
-        /// </summary>
-        public ICollection<string> NonSummarizableProperties { get; init; }
-
-        public ICollection<SummarizeMethod> NotSupportedSummarizeMethods { get; init; }
-        
-        public SummarizeRestrictions()
+        public virtual bool IsSummarizableProperty(string propertyName)
+        {
+            return false;
+        }
+
+        public virtual bool IsSummarizableMethod(SummarizeMethod method)
+        {
+            return false;
+        }
+
+        public SummarizeCapabilities()
         {
         }
     }
 
+    [Obsolete("preview")]
     public enum SummarizeMethod
     {
         None,
diff --git a/src/libraries/Microsoft.PowerFx.Core/Public/Values/DelegationParameters.cs b/src/libraries/Microsoft.PowerFx.Core/Public/Values/DelegationParameters.cs
index 9e3c9db056..f606401c19 100644
--- a/src/libraries/Microsoft.PowerFx.Core/Public/Values/DelegationParameters.cs
+++ b/src/libraries/Microsoft.PowerFx.Core/Public/Values/DelegationParameters.cs
@@ -73,6 +73,9 @@ public enum DelegationParameterFeatures
         // $apply
         Apply = 1 << 4,
 
+        // $apply = groupby((field1, ..), field with sum as TotalSum)
+        ApplyGroupBy = 1 << 5,
+
         /*
           To be implemented later when needed
          
diff --git a/src/tests/Microsoft.PowerFx.Core.Tests.Shared/PublicSurfaceTests.cs b/src/tests/Microsoft.PowerFx.Core.Tests.Shared/PublicSurfaceTests.cs
index 6a9a8368f3..352871be4b 100644
--- a/src/tests/Microsoft.PowerFx.Core.Tests.Shared/PublicSurfaceTests.cs
+++ b/src/tests/Microsoft.PowerFx.Core.Tests.Shared/PublicSurfaceTests.cs
@@ -202,6 +202,8 @@ public void PublicSurface_Tests()
                 "Microsoft.PowerFx.Core.Entities.IRefreshable",                
                 "Microsoft.PowerFx.Core.Entities.SelectionRestrictions",
                 "Microsoft.PowerFx.Core.Entities.SortRestrictions",
+                "Microsoft.PowerFx.Core.Entities.SummarizeCapabilities",
+                "Microsoft.PowerFx.Core.Entities.SummarizeMethod",
                 "Microsoft.PowerFx.Core.Entities.TableDelegationInfo",
                 "Microsoft.PowerFx.Core.Functions.Delegation.DelegationOperator",
                 "Microsoft.PowerFx.Core.Localization.ErrorResourceKey",