diff --git a/src/Squidex.Domain.Apps.Entities/Apps/AppDomainObject.cs b/src/Squidex.Domain.Apps.Entities/Apps/AppDomainObject.cs
index 411f4a8e8..2dedb3a7a 100644
--- a/src/Squidex.Domain.Apps.Entities/Apps/AppDomainObject.cs
+++ b/src/Squidex.Domain.Apps.Entities/Apps/AppDomainObject.cs
@@ -13,13 +13,12 @@ using Squidex.Domain.Apps.Entities.Apps.State;
 using Squidex.Domain.Apps.Events;
 using Squidex.Domain.Apps.Events.Apps;
 using Squidex.Infrastructure;
-using Squidex.Infrastructure.Commands;
 using Squidex.Infrastructure.EventSourcing;
 using Squidex.Infrastructure.Reflection;
 
 namespace Squidex.Domain.Apps.Entities.Apps
 {
-    public sealed class AppDomainObject : DomainObjectBase<AppState>
+    public sealed class AppDomainObject : SquidexDomainObjectBase<AppState>
     {
         private readonly InitialPatterns initialPatterns;
 
diff --git a/src/Squidex.Domain.Apps.Entities/Assets/AssetDomainObject.cs b/src/Squidex.Domain.Apps.Entities/Assets/AssetDomainObject.cs
index 103cd9981..360f9134c 100644
--- a/src/Squidex.Domain.Apps.Entities/Assets/AssetDomainObject.cs
+++ b/src/Squidex.Domain.Apps.Entities/Assets/AssetDomainObject.cs
@@ -9,13 +9,12 @@ using Squidex.Domain.Apps.Entities.Assets.Commands;
 using Squidex.Domain.Apps.Entities.Assets.State;
 using Squidex.Domain.Apps.Events.Assets;
 using Squidex.Infrastructure;
-using Squidex.Infrastructure.Commands;
 using Squidex.Infrastructure.EventSourcing;
 using Squidex.Infrastructure.Reflection;
 
 namespace Squidex.Domain.Apps.Entities.Assets
 {
-    public sealed class AssetDomainObject : DomainObjectBase<AssetState>
+    public sealed class AssetDomainObject : SquidexDomainObjectBase<AssetState>
     {
         public AssetDomainObject Create(CreateAsset command)
         {
diff --git a/src/Squidex.Domain.Apps.Entities/Contents/ContentDomainObject.cs b/src/Squidex.Domain.Apps.Entities/Contents/ContentDomainObject.cs
index 0b46b12d7..d9eb1fa1d 100644
--- a/src/Squidex.Domain.Apps.Entities/Contents/ContentDomainObject.cs
+++ b/src/Squidex.Domain.Apps.Entities/Contents/ContentDomainObject.cs
@@ -10,13 +10,12 @@ using Squidex.Domain.Apps.Entities.Contents.Commands;
 using Squidex.Domain.Apps.Entities.Contents.State;
 using Squidex.Domain.Apps.Events.Contents;
 using Squidex.Infrastructure;
-using Squidex.Infrastructure.Commands;
 using Squidex.Infrastructure.EventSourcing;
 using Squidex.Infrastructure.Reflection;
 
 namespace Squidex.Domain.Apps.Entities.Contents
 {
-    public sealed class ContentDomainObject : DomainObjectBase<ContentState>
+    public sealed class ContentDomainObject : SquidexDomainObjectBase<ContentState>
     {
         public ContentDomainObject Create(CreateContent command)
         {
diff --git a/src/Squidex.Domain.Apps.Entities/Rules/RuleDomainObject.cs b/src/Squidex.Domain.Apps.Entities/Rules/RuleDomainObject.cs
index bc05ac8bd..706b3e352 100644
--- a/src/Squidex.Domain.Apps.Entities/Rules/RuleDomainObject.cs
+++ b/src/Squidex.Domain.Apps.Entities/Rules/RuleDomainObject.cs
@@ -9,13 +9,12 @@ using Squidex.Domain.Apps.Entities.Rules.Commands;
 using Squidex.Domain.Apps.Entities.Rules.State;
 using Squidex.Domain.Apps.Events.Rules;
 using Squidex.Infrastructure;
-using Squidex.Infrastructure.Commands;
 using Squidex.Infrastructure.EventSourcing;
 using Squidex.Infrastructure.Reflection;
 
 namespace Squidex.Domain.Apps.Entities.Rules
 {
-    public sealed class RuleDomainObject : DomainObjectBase<RuleState>
+    public sealed class RuleDomainObject : SquidexDomainObjectBase<RuleState>
     {
         public void Create(CreateRule command)
         {
diff --git a/src/Squidex.Domain.Apps.Entities/Schemas/SchemaDomainObject.cs b/src/Squidex.Domain.Apps.Entities/Schemas/SchemaDomainObject.cs
index cc081ee28..d4c862953 100644
--- a/src/Squidex.Domain.Apps.Entities/Schemas/SchemaDomainObject.cs
+++ b/src/Squidex.Domain.Apps.Entities/Schemas/SchemaDomainObject.cs
@@ -12,13 +12,12 @@ using Squidex.Domain.Apps.Entities.Schemas.Commands;
 using Squidex.Domain.Apps.Entities.Schemas.State;
 using Squidex.Domain.Apps.Events.Schemas;
 using Squidex.Infrastructure;
-using Squidex.Infrastructure.Commands;
 using Squidex.Infrastructure.EventSourcing;
 using Squidex.Infrastructure.Reflection;
 
 namespace Squidex.Domain.Apps.Entities.Schemas
 {
-    public sealed class SchemaDomainObject : DomainObjectBase<SchemaState>
+    public sealed class SchemaDomainObject : SquidexDomainObjectBase<SchemaState>
     {
         private readonly FieldRegistry registry;
 
diff --git a/src/Squidex.Domain.Apps.Entities/SquidexDomainObjectBase.cs b/src/Squidex.Domain.Apps.Entities/SquidexDomainObjectBase.cs
new file mode 100644
index 000000000..63f0f94ed
--- /dev/null
+++ b/src/Squidex.Domain.Apps.Entities/SquidexDomainObjectBase.cs
@@ -0,0 +1,26 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using Squidex.Domain.Apps.Events;
+using Squidex.Infrastructure.Commands;
+using Squidex.Infrastructure.EventSourcing;
+
+namespace Squidex.Domain.Apps.Entities
+{
+    public abstract class SquidexDomainObjectBase<T> : DomainObjectBase<T> where T : IDomainState, new()
+    {
+        public override void RaiseEvent(Envelope<IEvent> @event)
+        {
+            if (@event.Payload is AppEvent appEvent)
+            {
+                @event.SetAppId(appEvent.AppId.Id);
+            }
+
+            base.RaiseEvent(@event);
+        }
+    }
+}
diff --git a/src/Squidex.Domain.Apps.Events/SquidexHeaderExtensions.cs b/src/Squidex.Domain.Apps.Events/SquidexHeaderExtensions.cs
new file mode 100644
index 000000000..0673d3b5b
--- /dev/null
+++ b/src/Squidex.Domain.Apps.Events/SquidexHeaderExtensions.cs
@@ -0,0 +1,28 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System;
+using System.Globalization;
+using Squidex.Infrastructure.EventSourcing;
+
+namespace Squidex.Domain.Apps.Events
+{
+    public static class SquidexHeaderExtensions
+    {
+        public static Guid AppId(this EnvelopeHeaders headers)
+        {
+            return headers[SquidexHeaders.AppId].ToGuid(CultureInfo.InvariantCulture);
+        }
+
+        public static Envelope<T> SetAppId<T>(this Envelope<T> envelope, Guid value) where T : class
+        {
+            envelope.Headers.Set(SquidexHeaders.AppId, value);
+
+            return envelope;
+        }
+    }
+}
diff --git a/src/Squidex.Domain.Apps.Events/SquidexHeaders.cs b/src/Squidex.Domain.Apps.Events/SquidexHeaders.cs
new file mode 100644
index 000000000..e2f610a10
--- /dev/null
+++ b/src/Squidex.Domain.Apps.Events/SquidexHeaders.cs
@@ -0,0 +1,14 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+namespace Squidex.Domain.Apps.Events
+{
+    public static class SquidexHeaders
+    {
+        public static readonly string AppId = "AppId";
+    }
+}
diff --git a/src/Squidex.Infrastructure.GetEventStore/EventSourcing/ProjectionClient.cs b/src/Squidex.Infrastructure.GetEventStore/EventSourcing/ProjectionClient.cs
index 203dd0050..c4c41ef6d 100644
--- a/src/Squidex.Infrastructure.GetEventStore/EventSourcing/ProjectionClient.cs
+++ b/src/Squidex.Infrastructure.GetEventStore/EventSourcing/ProjectionClient.cs
@@ -51,8 +51,8 @@ namespace Squidex.Infrastructure.EventSourcing
                 $@"fromAll()
                     .when({{
                         $any: function (s, e) {{
-                            if (e.streamId.indexOf('{prefix}') === 0 && e.data.{property}) {{
-                                linkTo('{name}-' + e.data.{property}, e);
+                            if (e.streamId.indexOf('{prefix}') === 0 && e.metadata.{property}) {{
+                                linkTo('{name}-' + e.metadata.{property}, e);
                             }}
                         }}
                     }});";
diff --git a/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEvent.cs b/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEvent.cs
index dfff1ef94..62d15ca20 100644
--- a/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEvent.cs
+++ b/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEvent.cs
@@ -7,7 +7,6 @@
 
 using MongoDB.Bson.Serialization.Attributes;
 using Newtonsoft.Json.Linq;
-using Squidex.Infrastructure.Reflection;
 
 namespace Squidex.Infrastructure.EventSourcing
 {
@@ -15,7 +14,7 @@ namespace Squidex.Infrastructure.EventSourcing
     {
         [BsonElement]
         [BsonRequired]
-        public JToken Payload { get; set; }
+        public string Payload { get; set; }
 
         [BsonElement]
         [BsonRequired]
@@ -25,18 +24,14 @@ namespace Squidex.Infrastructure.EventSourcing
         [BsonRequired]
         public string Type { get; set; }
 
-        public MongoEvent()
+        public static MongoEvent FromEventData(EventData data)
         {
-        }
-
-        public MongoEvent(EventData data)
-        {
-            SimpleMapper.Map(data, this);
+            return new MongoEvent { Type = data.Type, Metadata = data.Metadata, Payload = data.ToString() };
         }
 
         public EventData ToEventData()
         {
-            return SimpleMapper.Map(this, new EventData());
+            return new EventData { Type = Type, Metadata = Metadata, Payload = JObject.Parse(Payload) };
         }
     }
 }
\ No newline at end of file
diff --git a/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Reader.cs b/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Reader.cs
index ccc7737e9..eed2d0bce 100644
--- a/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Reader.cs
+++ b/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Reader.cs
@@ -167,7 +167,7 @@ namespace Squidex.Infrastructure.EventSourcing
 
         private static string CreateIndexPath(string property)
         {
-            return $"Events.Payload.{property}";
+            return $"Events.Metadata.{property}";
         }
     }
 }
\ No newline at end of file
diff --git a/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Writer.cs b/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Writer.cs
index 016d3d837..937b66050 100644
--- a/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Writer.cs
+++ b/src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Writer.cs
@@ -108,7 +108,7 @@ namespace Squidex.Infrastructure.EventSourcing
 
             foreach (var e in events)
             {
-                var mongoEvent = new MongoEvent(e);
+                var mongoEvent = MongoEvent.FromEventData(e);
 
                 commitEvents[i++] = mongoEvent;
             }
diff --git a/src/Squidex.Infrastructure.MongoDb/MongoDb/BsonJsonConvention.cs b/src/Squidex.Infrastructure.MongoDb/MongoDb/BsonJsonConvention.cs
index 2a8d6e572..2d2dc8939 100644
--- a/src/Squidex.Infrastructure.MongoDb/MongoDb/BsonJsonConvention.cs
+++ b/src/Squidex.Infrastructure.MongoDb/MongoDb/BsonJsonConvention.cs
@@ -12,6 +12,7 @@ using MongoDB.Bson.Serialization;
 using MongoDB.Bson.Serialization.Conventions;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
+using Squidex.Infrastructure.MongoDb;
 
 namespace Squidex.Infrastructure.MongoDb
 {
diff --git a/src/Squidex.Infrastructure/Commands/DomainObjectBase.cs b/src/Squidex.Infrastructure/Commands/DomainObjectBase.cs
index 7327a058d..b054d8729 100644
--- a/src/Squidex.Infrastructure/Commands/DomainObjectBase.cs
+++ b/src/Squidex.Infrastructure/Commands/DomainObjectBase.cs
@@ -45,13 +45,13 @@ namespace Squidex.Infrastructure.Commands
             RaiseEvent(Envelope.Create(@event));
         }
 
-        public void RaiseEvent<TEvent>(Envelope<TEvent> @event) where TEvent : class, IEvent
+        public virtual void RaiseEvent(Envelope<IEvent> @event)
         {
             Guard.NotNull(@event, nameof(@event));
 
             @event.SetAggregateId(id);
 
-            ApplyEvent(@event.To<IEvent>());
+            ApplyEvent(@event);
 
             snapshot.Version++;
 
diff --git a/src/Squidex.Infrastructure/Json/NamedGuidIdConverter.cs b/src/Squidex.Infrastructure/Json/NamedGuidIdConverter.cs
index 4499419d3..c4c83790f 100644
--- a/src/Squidex.Infrastructure/Json/NamedGuidIdConverter.cs
+++ b/src/Squidex.Infrastructure/Json/NamedGuidIdConverter.cs
@@ -25,19 +25,14 @@ namespace Squidex.Infrastructure.Json
                 throw new JsonException($"Expected String, but got {reader.TokenType}.");
             }
 
-            var parts = reader.Value.ToString().Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
-
-            if (parts.Length < 2)
+            try
             {
-                throw new JsonException("Named id must have more than 2 parts divided by commata.");
+                return NamedId<Guid>.Parse(reader.Value.ToString(), Guid.TryParse);
             }
-
-            if (!Guid.TryParse(parts[0], out var id))
+            catch (ArgumentException ex)
             {
-                throw new JsonException("Named id must be a valid guid.");
+                throw new JsonException(ex.Message);
             }
-
-            return new NamedId<Guid>(id, string.Join(",", parts.Skip(1)));
         }
     }
 }
diff --git a/src/Squidex.Infrastructure/Json/NamedLongIdConverter.cs b/src/Squidex.Infrastructure/Json/NamedLongIdConverter.cs
index 4efb97dc0..5054b4dc7 100644
--- a/src/Squidex.Infrastructure/Json/NamedLongIdConverter.cs
+++ b/src/Squidex.Infrastructure/Json/NamedLongIdConverter.cs
@@ -25,19 +25,14 @@ namespace Squidex.Infrastructure.Json
                 throw new JsonException($"Expected String, but got {reader.TokenType}.");
             }
 
-            var parts = reader.Value.ToString().Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
-
-            if (parts.Length < 2)
+            try
             {
-                throw new JsonException("Named id must have more than 2 parts divided by commata.");
+                return NamedId<long>.Parse(reader.Value.ToString(), long.TryParse);
             }
-
-            if (!long.TryParse(parts[0], out var id))
+            catch (ArgumentException ex)
             {
-                throw new JsonException("Named id must be a valid long.");
+                throw new JsonException(ex.Message);
             }
-
-            return new NamedId<long>(id, string.Join(",", parts.Skip(1)));
         }
     }
 }
diff --git a/src/Squidex.Infrastructure/Migrations/Migrator.cs b/src/Squidex.Infrastructure/Migrations/Migrator.cs
index e0f8feffe..0ba832d9e 100644
--- a/src/Squidex.Infrastructure/Migrations/Migrator.cs
+++ b/src/Squidex.Infrastructure/Migrations/Migrator.cs
@@ -17,7 +17,7 @@ namespace Squidex.Infrastructure.Migrations
         private readonly IMigrationStatus migrationStatus;
         private readonly IMigrationPath migrationPath;
 
-        public int LockWaitMs { get; set; } = 5000;
+        public int LockWaitMs { get; set; } = 500;
 
         public Migrator(IMigrationStatus migrationStatus, IMigrationPath migrationPath, ISemanticLog log)
         {
diff --git a/src/Squidex.Infrastructure/NamedId.cs b/src/Squidex.Infrastructure/NamedId.cs
index 0b16475fe..e8f99f6d4 100644
--- a/src/Squidex.Infrastructure/NamedId.cs
+++ b/src/Squidex.Infrastructure/NamedId.cs
@@ -6,9 +6,12 @@
 // ==========================================================================
 
 using System;
+using System.Linq;
 
 namespace Squidex.Infrastructure
 {
+    public delegate bool Parser<T>(string input, out T result);
+
     public sealed class NamedId<T> : IEquatable<NamedId<T>>
     {
         public T Id { get; }
@@ -44,5 +47,24 @@ namespace Squidex.Infrastructure
         {
             return (Id.GetHashCode() * 397) ^ Name.GetHashCode();
         }
+
+        public static NamedId<T> Parse(string value, Parser<T> parser)
+        {
+            Guard.NotNull(value, nameof(value));
+
+            var parts = value.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
+
+            if (parts.Length < 2)
+            {
+                throw new ArgumentException("Named id must have more than 2 parts divided by commata.");
+            }
+
+            if (!parser(parts[0], out var id))
+            {
+                throw new ArgumentException("Named id must be a valid guid.");
+            }
+
+            return new NamedId<T>(id, string.Join(",", parts.Skip(1)));
+        }
     }
 }
diff --git a/tools/Migrate_01/MigrationPath.cs b/tools/Migrate_01/MigrationPath.cs
index 682c3c704..365bdf896 100644
--- a/tools/Migrate_01/MigrationPath.cs
+++ b/tools/Migrate_01/MigrationPath.cs
@@ -13,16 +13,16 @@ using Squidex.Infrastructure.Migrations;
 
 namespace Migrate_01
 {
-    public class MigrationMatrix
+    public sealed class MigrationPath : IMigrationPath
     {
         private readonly IServiceProvider serviceProvider;
 
-        public MigrationMatrix(IServiceProvider serviceProvider)
+        public MigrationPath(IServiceProvider serviceProvider)
         {
             this.serviceProvider = serviceProvider;
         }
 
-        public (int Version, IEnumerable<IMigration> Migrations) MigrationPath(int version)
+        public (int Version, IEnumerable<IMigration> Migrations) GetNext(int version)
         {
             switch (version)
             {
diff --git a/tools/Migrate_01/Migrations/ConvertEventStore.cs b/tools/Migrate_01/Migrations/ConvertEventStore.cs
index 83715a400..20c74e8ab 100644
--- a/tools/Migrate_01/Migrations/ConvertEventStore.cs
+++ b/tools/Migrate_01/Migrations/ConvertEventStore.cs
@@ -5,11 +5,16 @@
 //  All rights reserved. Licensed under the MIT license.
 // ==========================================================================
 
+using System;
 using System.Threading.Tasks;
 using MongoDB.Bson;
 using MongoDB.Driver;
+using Newtonsoft.Json.Linq;
+using Squidex.Domain.Apps.Events;
+using Squidex.Infrastructure;
 using Squidex.Infrastructure.EventSourcing;
 using Squidex.Infrastructure.Migrations;
+using Squidex.Infrastructure.MongoDb;
 
 namespace Migrate_01.Migrations
 {
@@ -34,10 +39,16 @@ namespace Migrate_01.Migrations
                 {
                     foreach (BsonDocument @event in commit["Events"].AsBsonArray)
                     {
-                        @event.Remove("EventId");
+                        var meta = JObject.Parse(@event["Metadata"].AsString);
+                        var data = JObject.Parse(@event["Payload"].AsString);
+
+                        if (data.TryGetValue("appId", out var appId))
+                        {
+                            meta[SquidexHeaders.AppId] = NamedId<Guid>.Parse(appId.ToString(), Guid.TryParse).Id;
+                        }
 
-                        @event["Payload"] = BsonDocument.Parse(@event["Payload"].AsString);
-                        @event["Metadata"] = BsonDocument.Parse(@event["Metadata"].AsString);
+                        @event.Remove("EventId");
+                        @event["Metadata"] = meta.ToBson();
                     }
 
                     await collection.ReplaceOneAsync(filter.Eq("_id", commit["_id"].AsString), commit);