diff --git a/backend/Origam.Server/Common/ChangeInfo.cs b/backend/Origam.Server/Common/ChangeInfo.cs
index d9dc9070f6..6111b06c75 100644
--- a/backend/Origam.Server/Common/ChangeInfo.cs
+++ b/backend/Origam.Server/Common/ChangeInfo.cs
@@ -19,27 +19,7 @@
 */
 #endregion
 
-#region license
-/*
-Copyright 2005 - 2021 Advantage Solutions, s. r. o.
-
-This file is part of ORIGAM.
-
-ORIGAM is free software: you can redistribute it and/or modify
-it under the terms of the GNU Affero General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-ORIGAM is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
-GNU Affero General Public License for more details.
-
-You should have received a copy of the GNU Affero General Public License
-along with ORIGAM.  If not, see<http://www.gnu.org/licenses/>.
-*/
-#endregion
-
+using System;
 using Origam.Rule;
 
 namespace Origam.Server
@@ -155,5 +135,32 @@ public static ChangeInfo CleanDataChangeInfo()
             ci.Operation = Operation.DeleteAllData;
             return ci;
         }
+
+        protected bool Equals(ChangeInfo other)
+        {
+            return entity == other.entity && operation == other.operation && Equals(objectId, other.objectId);
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(null, obj))
+            {
+                return false;
+            }
+            if (ReferenceEquals(this, obj))
+            {
+                return true;
+            }
+            if (obj.GetType() != this.GetType())
+            {
+                return false;
+            }
+            return Equals((ChangeInfo)obj);
+        }
+
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(entity, (int)operation, objectId);
+        }
     }
 }
\ No newline at end of file
diff --git a/backend/Origam.Server/Controller/SessionController.cs b/backend/Origam.Server/Controller/SessionController.cs
index 290931577e..8753724855 100644
--- a/backend/Origam.Server/Controller/SessionController.cs
+++ b/backend/Origam.Server/Controller/SessionController.cs
@@ -21,6 +21,7 @@
 
 using System;
 using System.Collections;
+using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using System.Data;
 using System.Threading;
@@ -172,7 +173,7 @@ public IActionResult UpdateRow([FromBody]UpdateRowData updateData)
             return RunWithErrorHandler(() =>
             {
                 SessionStore ss = sessionObjects.SessionManager.GetSession(updateData.SessionFormIdentifier);
-                IList output = ss.UpdateObject(
+                IEnumerable<ChangeInfo> output = ss.UpdateObject(
                     entity: updateData.Entity,
                     id: updateData.Id,
                     property: updateData.Property,
diff --git a/backend/Origam.Server/ServerCoreUIService.cs b/backend/Origam.Server/ServerCoreUIService.cs
index ee6e5da3ee..43097325b2 100644
--- a/backend/Origam.Server/ServerCoreUIService.cs
+++ b/backend/Origam.Server/ServerCoreUIService.cs
@@ -382,7 +382,7 @@ public IList DeleteObject(DeleteObjectInput input)
         public IList DeleteObjectInOrderedList(DeleteObjectInOrderedListInput input)
         {
             SessionStore ss = sessionManager.GetSession(new Guid(input.SessionFormIdentifier));
-            ArrayList changes = ss.UpdateObjectBatch(input.Entity, input.OrderProperty, input.UpdatedOrderValues);
+            List<ChangeInfo> changes = ss.UpdateObjectBatch(input.Entity, input.OrderProperty, input.UpdatedOrderValues);
             changes.AddRange(ss.DeleteObject(input.Entity, input.Id));
             Task.Run(() => SecurityTools.CreateUpdateOrigamOnlineUser(
                 SecurityManager.CurrentPrincipal.Identity.Name,
@@ -927,7 +927,7 @@ public ArrayList GetPendingChanges(Guid sessionFormIdentifier)
             sessionStore.PendingChanges = null;
             return changes ?? new ArrayList();
         }
-        public ArrayList GetChanges(ChangesInput input)
+        public List<ChangeInfo> GetChanges(ChangesInput input)
         {
             var sessionStore = sessionManager.GetSession(
                 input.SessionFormIdentifier);
diff --git a/backend/Origam.Server/Session Stores/SaveableSessionStore.cs b/backend/Origam.Server/Session Stores/SaveableSessionStore.cs
index 88fd0160c2..8ab74f0dee 100644
--- a/backend/Origam.Server/Session Stores/SaveableSessionStore.cs	
+++ b/backend/Origam.Server/Session Stores/SaveableSessionStore.cs	
@@ -197,7 +197,7 @@ internal virtual object Save()
             return listOfChanges;
         }
 
-        public override ArrayList CreateObject(string entity, IDictionary<string, object> values, 
+        public override List<ChangeInfo> CreateObject(string entity, IDictionary<string, object> values, 
             IDictionary<string, object> parameters, string requestingGrid)
         {
             if (this.Template == null || !this.Template.Entity.Name.Equals(entity))
@@ -225,7 +225,7 @@ internal virtual object Save()
 
                 DataRow newRow = table.Rows.Find(key);
                 NewRowToDataList(newRow);
-                ArrayList listOfChanges = GetChangesByRow(requestingGrid, 
+                List<ChangeInfo> listOfChanges = GetChangesByRow(requestingGrid, 
                     newRow, Operation.Create, this.Data.HasErrors, 
                     this.Data.HasChanges(), true);
 
@@ -233,9 +233,9 @@ internal virtual object Save()
             }
         }
 
-        public override ArrayList UpdateObject(string entity, object id, string property, object newValue)
+        public override IEnumerable<ChangeInfo> UpdateObject(string entity, object id, string property, object newValue)
         {
-            ArrayList result = new ArrayList();
+            var result = new HashSet<ChangeInfo>();
             InitializeFieldDependencies();
             DataTable table = GetTable(entity, this.Data);
             Guid dsEntityId = (Guid)table.ExtendedProperties["Id"];
@@ -248,7 +248,7 @@ public override ArrayList UpdateObject(string entity, object id, string property
                     foreach(Guid dependentColumnId in _entityFieldDependencies[dsEntityId][fieldId])
                     {
                         string dependentColumnName = ColumnNameById(table, dependentColumnId);
-                        IList changes;
+                        IEnumerable<ChangeInfo> changes;
                         try
                         {
                             changes = this.UpdateObject(entity, id, dependentColumnName, null);
@@ -260,7 +260,7 @@ public override ArrayList UpdateObject(string entity, object id, string property
                                 dependentColumnName, property, entity, e.Message));
                         }
 
-                        foreach (object o in changes)
+                        foreach (var o in changes)
                         {
                             result.Add(o);
                         }
@@ -268,8 +268,8 @@ public override ArrayList UpdateObject(string entity, object id, string property
                 }
             }
 
-            IList baseChanges = base.UpdateObject(entity, id, property, newValue);
-            foreach (object o in baseChanges)
+            IEnumerable<ChangeInfo> baseChanges = base.UpdateObject(entity, id, property, newValue);
+            foreach (var o in baseChanges)
             {
                 result.Add(o);
             }
diff --git a/backend/Origam.Server/Session Stores/SessionStore.cs b/backend/Origam.Server/Session Stores/SessionStore.cs
index 9a48768e5f..e47ec05669 100644
--- a/backend/Origam.Server/Session Stores/SessionStore.cs	
+++ b/backend/Origam.Server/Session Stores/SessionStore.cs	
@@ -827,7 +827,7 @@ private static bool IsInColumns(DataColumn searchedColumn, DataColumn[] columns)
             return false;
         }
 
-        public ArrayList GetChangesByRow(
+        public List<ChangeInfo> GetChangesByRow(
             string requestingGrid, DataRow row, Operation operation, 
             bool hasErrors, bool hasChanges, bool fromTemplate)
         {
@@ -835,12 +835,12 @@ private static bool IsInColumns(DataColumn searchedColumn, DataColumn[] columns)
                 hasErrors, hasChanges, fromTemplate);
         }
 
-        internal ArrayList GetChangesByRow(
+        internal List<ChangeInfo> GetChangesByRow(
             string requestingGrid, DataRow row, Operation operation, 
             Hashtable ignoreKeys, bool includeRowStates, bool hasErrors, 
             bool hasChanges, bool fromTemplate)
         {
-            ArrayList listOfChanges = new ArrayList();
+            var listOfChanges = new List<ChangeInfo>();
             DataRow rootRow = DatasetTools.RootRow(row);
             DatasetTools.CheckRowErrorRecursive(rootRow, null, false);
 
@@ -925,20 +925,20 @@ private static void CloneErrors(DataRow sourceRow, DataRow destinationRow)
             }
         }
 
-        public ArrayList GetChanges(string entity, object id, Operation operation, bool hasErrors, bool hasChanges)
+        public List<ChangeInfo> GetChanges(string entity, object id, Operation operation, bool hasErrors, bool hasChanges)
         {
             return GetChangesByRow(null, this.GetSessionRow(entity, id), 
                 operation, hasErrors, hasChanges, false);
         }
 
-        public ArrayList GetChanges(string entity, object id, Operation operation, Hashtable ignoreKeys, bool includeRowStates, bool hasErrors, bool hasChanges)
+        public List<ChangeInfo> GetChanges(string entity, object id, Operation operation, Hashtable ignoreKeys, bool includeRowStates, bool hasErrors, bool hasChanges)
         {
             return GetChangesByRow(null, this.GetSessionRow(entity, id), 
                 operation, ignoreKeys, includeRowStates, hasErrors, hasChanges,
                 false);
         }
 
-        private void GetChangesRecursive(ArrayList changes, string requestingGrid, DataRow row, Operation operation, DataRow changedRow, bool allDetails, Hashtable ignoreKeys, bool includeRowStates)
+        private void GetChangesRecursive(List<ChangeInfo> changes, string requestingGrid, DataRow row, Operation operation, DataRow changedRow, bool allDetails, Hashtable ignoreKeys, bool includeRowStates)
         {
             if (row.RowState != DataRowState.Deleted && row.RowState != DataRowState.Detached)
             {
@@ -1488,7 +1488,7 @@ public bool IsLazyLoadedEntity(string entity)
         }
 
         #region CUD
-        public virtual ArrayList CreateObject(string entity, IDictionary<string, object> values,
+        public virtual List<ChangeInfo> CreateObject(string entity, IDictionary<string, object> values,
             IDictionary<string, object> parameters, string requestingGrid)
         {
             lock (_lock)
@@ -1585,7 +1585,7 @@ public bool IsLazyLoadedEntity(string entity)
 
                 NewRowToDataList(newRow);
 
-                ArrayList listOfChanges = GetChangesByRow(requestingGrid, 
+                List<ChangeInfo> listOfChanges = GetChangesByRow(requestingGrid, 
                     newRow, Operation.Create, this.Data.HasErrors, 
                     this.Data.HasChanges(), false);
 
@@ -1593,7 +1593,7 @@ public bool IsLazyLoadedEntity(string entity)
             }
         }
 
-        public virtual ArrayList UpdateObject(string entity, object id, string property, object newValue)
+        public virtual IEnumerable<ChangeInfo> UpdateObject(string entity, object id, string property, object newValue)
         {
             lock (_lock)
             {
@@ -1618,7 +1618,7 @@ public virtual ArrayList UpdateObject(string entity, object id, string property,
                 {
                     UpdateRowColumn(property, newValue, profile, row);
                 }
-                ArrayList listOfChanges = GetChangesByRow(null, row,
+                List<ChangeInfo> listOfChanges = GetChangesByRow(null, row,
                     Operation.Update, this.Data.HasErrors, 
                     this.Data.HasChanges(), false);
                 if (!this.Data.HasChanges())
@@ -1748,7 +1748,7 @@ private static void UpdateRowValue(string property, object newValue, DataRow row
             }
         }
 
-        public virtual ArrayList DeleteObject(string entity, object id)
+        public virtual List<ChangeInfo> DeleteObject(string entity, object id)
         {
             lock(_lock)
             {
@@ -1757,7 +1757,7 @@ public virtual ArrayList DeleteObject(string entity, object id)
                 DataSet dataset = row.Table.DataSet;
 
                 // get the changes for the deleted row before we actually deleted, because then the row would be inaccessible
-                ArrayList deletedItems = new ArrayList();
+                var deletedItems = new List<ChangeInfo>();
                 Dictionary<string, List<DeletedRowInfo>> backup = BackupDeletedRows(row);
                 object[] listRowBackup = null;
 
@@ -1800,7 +1800,7 @@ public virtual ArrayList DeleteObject(string entity, object id)
                     // handle rules for the data changes after the row has been deleted
                     this.RuleHandler.OnRowDeleted((DataRow[])parentRows.ToArray(typeof(DataRow)), row, this.XmlData, this.RuleSet, this.RuleEngine);
 
-                    ArrayList listOfChanges = new ArrayList();
+                    var listOfChanges = new List<ChangeInfo>();
 
 
                     // get the changes - from root - e.g. recalculated totals after deletion
@@ -1831,7 +1831,8 @@ public virtual ArrayList DeleteObject(string entity, object id)
                             table.AcceptChanges();
                         }
                         // save the data
-                        listOfChanges.AddRange((IList)this.ExecuteAction(SessionStore.ACTION_SAVE));
+                        var actionResult = ((IList)ExecuteAction(ACTION_SAVE)).ToList<ChangeInfo>();
+                        listOfChanges.AddRange(actionResult);
                     }
                     return listOfChanges;
                 }
@@ -1947,7 +1948,7 @@ private static void BackupChildRows(DataRow parentRow, Dictionary<string, List<D
             }
         }
 
-        public ArrayList CopyObject(string entity, object originalId,
+        public List<ChangeInfo> CopyObject(string entity, object originalId,
             string requestingGrid, ArrayList entities,
             IDictionary<string, object> forcedValues)
         {
@@ -2145,7 +2146,7 @@ public virtual ChangeInfo GetRow(string entity, object id)
         }
         #endregion
 
-        private void AddChildDeletedItems(ArrayList deletedItems, DataRow deletedRow)
+        private void AddChildDeletedItems(List<ChangeInfo> deletedItems, DataRow deletedRow)
         {
             foreach (DataRelation child in deletedRow.Table.ChildRelations)
             {
@@ -2160,9 +2161,9 @@ private void AddChildDeletedItems(ArrayList deletedItems, DataRow deletedRow)
 
         #endregion
 
-        public ArrayList UpdateObjectBatch(string entity, string property, Hashtable values)
+        public List<ChangeInfo> UpdateObjectBatch(string entity, string property, Hashtable values)
         {
-            ArrayList result = new ArrayList();
+            var result = new List<ChangeInfo>();
 
             lock (_lock)
             {
@@ -2175,9 +2176,9 @@ public ArrayList UpdateObjectBatch(string entity, string property, Hashtable val
             return result;
         }
 
-        public ArrayList UpdateObjectEx(string entity, object id, Hashtable values)
+        public List<ChangeInfo> UpdateObjectEx(string entity, object id, Hashtable values)
         {
-            ArrayList result = new ArrayList();
+            var result = new List<ChangeInfo>();
 
             lock (_lock)
             {
@@ -2189,9 +2190,9 @@ public ArrayList UpdateObjectEx(string entity, object id, Hashtable values)
 
             return result;
         }  
-        public ArrayList UpdateObjectBatch(string entity, UpdateData[] updateDataArray) 
+        public List<ChangeInfo> UpdateObjectBatch(string entity, UpdateData[] updateDataArray) 
         {
-            ArrayList result = new ArrayList();
+            var result = new List<ChangeInfo>();
 
             lock (_lock)
             {