diff --git a/src/BuildingBlocks/BuildingBlocks.csproj b/src/BuildingBlocks/BuildingBlocks.csproj
index 2da37be..3135285 100644
--- a/src/BuildingBlocks/BuildingBlocks.csproj
+++ b/src/BuildingBlocks/BuildingBlocks.csproj
@@ -35,6 +35,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="7.0.1" />
     <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="7.0.0" />
     <PackageReference Include="Mongo2Go" Version="3.1.3" />
+    <PackageReference Include="Npgsql" Version="7.0.1" />
     <PackageReference Include="NSubstitute" Version="4.4.0" />
     <PackageReference Include="OpenTelemetry.Instrumentation.GrpcNetClient" Version="1.0.0-rc9.7" />
     <PackageReference Include="Polly" Version="7.2.3" />
diff --git a/src/BuildingBlocks/Core/Model/Aggregate.cs b/src/BuildingBlocks/Core/Model/Aggregate.cs
index 42c87ca..14697d5 100644
--- a/src/BuildingBlocks/Core/Model/Aggregate.cs
+++ b/src/BuildingBlocks/Core/Model/Aggregate.cs
@@ -25,7 +25,7 @@ namespace BuildingBlocks.Core.Model
             return dequeuedEvents;
         }
 
-        public long Version { get; set; } = -1;
+        public long Version { get; set; }
 
         public TId Id { get; set;  }
     }
diff --git a/src/BuildingBlocks/EFCore/AppDbContextBase.cs b/src/BuildingBlocks/EFCore/AppDbContextBase.cs
index 88db419..57b4720 100644
--- a/src/BuildingBlocks/EFCore/AppDbContextBase.cs
+++ b/src/BuildingBlocks/EFCore/AppDbContextBase.cs
@@ -7,13 +7,16 @@ using Microsoft.EntityFrameworkCore.Storage;
 
 namespace BuildingBlocks.EFCore;
 
+using System.Data;
+
 public abstract class AppDbContextBase : DbContext, IDbContext
 {
     private readonly ICurrentUserProvider _currentUserProvider;
 
     private IDbContextTransaction _currentTransaction;
 
-    protected AppDbContextBase(DbContextOptions options, ICurrentUserProvider currentUserProvider = null) : base(options)
+    protected AppDbContextBase(DbContextOptions options, ICurrentUserProvider currentUserProvider = null) :
+        base(options)
     {
         _currentUserProvider = currentUserProvider;
     }
@@ -30,7 +33,7 @@ public abstract class AppDbContextBase : DbContext, IDbContext
             return;
         }
 
-        _currentTransaction ??= await Database.BeginTransactionAsync(cancellationToken);
+        _currentTransaction ??= await Database.BeginTransactionAsync(IsolationLevel.ReadCommitted, cancellationToken);
     }
 
     public async Task CommitTransactionAsync(CancellationToken cancellationToken = default)
@@ -68,7 +71,16 @@ public abstract class AppDbContextBase : DbContext, IDbContext
     public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
     {
         OnBeforeSaving();
-        return base.SaveChangesAsync(cancellationToken);
+        try
+        {
+            return base.SaveChangesAsync(cancellationToken);
+        }
+        catch (DbUpdateConcurrencyException ex)
+        {
+            var data = ex.Entries.Single();
+            data.OriginalValues.SetValues(data.GetDatabaseValues() ?? throw new InvalidOperationException());
+            return base.SaveChangesAsync(cancellationToken);
+        }
     }
 
     public IReadOnlyList<IDomainEvent> GetDomainEvents()
@@ -104,7 +116,6 @@ public abstract class AppDbContextBase : DbContext, IDbContext
                     case EntityState.Added:
                         entry.Entity.CreatedBy = userId;
                         entry.Entity.CreatedAt = DateTime.Now;
-                        entry.Entity.Version++;
                         break;
 
                     case EntityState.Modified:
diff --git a/src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230113183839_initial.Designer.cs b/src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230120222214_initial.Designer.cs
similarity index 98%
rename from src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230113183839_initial.Designer.cs
rename to src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230120222214_initial.Designer.cs
index e6ae47d..3265c90 100644
--- a/src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230113183839_initial.Designer.cs
+++ b/src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230120222214_initial.Designer.cs
@@ -12,7 +12,7 @@ using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
 namespace BuildingBlocks.PersistMessageProcessor.Data.Migrations
 {
     [DbContext(typeof(PersistMessageDbContext))]
-    [Migration("20230113183839_initial")]
+    [Migration("20230120222214_initial")]
     partial class initial
     {
         /// <inheritdoc />
diff --git a/src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230113183839_initial.cs b/src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230120222214_initial.cs
similarity index 100%
rename from src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230113183839_initial.cs
rename to src/BuildingBlocks/PersistMessageProcessor/Data/Migrations/20230120222214_initial.cs
diff --git a/src/Services/Flight/src/Flight/Aircrafts/Models/Aircraft.cs b/src/Services/Flight/src/Flight/Aircrafts/Models/Aircraft.cs
index 6a67276..7c37fb5 100644
--- a/src/Services/Flight/src/Flight/Aircrafts/Models/Aircraft.cs
+++ b/src/Services/Flight/src/Flight/Aircrafts/Models/Aircraft.cs
@@ -1,5 +1,4 @@
 using BuildingBlocks.Core.Model;
-using BuildingBlocks.IdsGenerator;
 using Flight.Aircrafts.Features.CreateAircraft.Events.Domain.V1;
 
 namespace Flight.Aircrafts.Models;
diff --git a/src/Services/Flight/src/Flight/Data/Configurations/AircraftConfiguration.cs b/src/Services/Flight/src/Flight/Data/Configurations/AircraftConfiguration.cs
index 2af92aa..71fc974 100644
--- a/src/Services/Flight/src/Flight/Data/Configurations/AircraftConfiguration.cs
+++ b/src/Services/Flight/src/Flight/Data/Configurations/AircraftConfiguration.cs
@@ -8,8 +8,13 @@ public class AircraftConfiguration : IEntityTypeConfiguration<Aircraft>
 {
     public void Configure(EntityTypeBuilder<Aircraft> builder)
     {
+
         builder.ToTable(nameof(Aircraft));
         builder.HasKey(r => r.Id);
         builder.Property(r => r.Id).ValueGeneratedNever();
+
+
+        // // ref: https://learn.microsoft.com/en-us/ef/core/saving/concurrency?tabs=fluent-api
+        builder.Property(r => r.Version).IsConcurrencyToken();
     }
 }
diff --git a/src/Services/Flight/src/Flight/Data/Configurations/AirportConfiguration.cs b/src/Services/Flight/src/Flight/Data/Configurations/AirportConfiguration.cs
index 8fc776a..b3f475b 100644
--- a/src/Services/Flight/src/Flight/Data/Configurations/AirportConfiguration.cs
+++ b/src/Services/Flight/src/Flight/Data/Configurations/AirportConfiguration.cs
@@ -8,9 +8,14 @@ public class AirportConfiguration: IEntityTypeConfiguration<Airport>
 {
     public void Configure(EntityTypeBuilder<Airport> builder)
     {
+
         builder.ToTable(nameof(Airport));
 
         builder.HasKey(r => r.Id);
         builder.Property(r => r.Id).ValueGeneratedNever();
+
+
+        // // ref: https://learn.microsoft.com/en-us/ef/core/saving/concurrency?tabs=fluent-api
+        builder.Property(r => r.Version).IsConcurrencyToken();
     }
 }
diff --git a/src/Services/Flight/src/Flight/Data/Configurations/FlightConfiguration.cs b/src/Services/Flight/src/Flight/Data/Configurations/FlightConfiguration.cs
index 181dbab..42e549e 100644
--- a/src/Services/Flight/src/Flight/Data/Configurations/FlightConfiguration.cs
+++ b/src/Services/Flight/src/Flight/Data/Configurations/FlightConfiguration.cs
@@ -17,6 +17,10 @@ public class FlightConfiguration : IEntityTypeConfiguration<Flights.Models.Fligh
         builder.HasKey(r => r.Id);
         builder.Property(r => r.Id).ValueGeneratedNever();
 
+
+        // // ref: https://learn.microsoft.com/en-us/ef/core/saving/concurrency?tabs=fluent-api
+        builder.Property(r => r.Version).IsConcurrencyToken();
+
         builder
             .HasOne<Aircraft>()
             .WithMany()
diff --git a/src/Services/Flight/src/Flight/Data/Configurations/SeatConfiguration.cs b/src/Services/Flight/src/Flight/Data/Configurations/SeatConfiguration.cs
index 0ff9083..e1e6e0f 100644
--- a/src/Services/Flight/src/Flight/Data/Configurations/SeatConfiguration.cs
+++ b/src/Services/Flight/src/Flight/Data/Configurations/SeatConfiguration.cs
@@ -16,6 +16,9 @@ public class SeatConfiguration : IEntityTypeConfiguration<Seat>
         builder.HasKey(r => r.Id);
         builder.Property(r => r.Id).ValueGeneratedNever();
 
+        // // ref: https://learn.microsoft.com/en-us/ef/core/saving/concurrency?tabs=fluent-api
+         builder.Property(r => r.Version).IsConcurrencyToken();
+
         builder
             .HasOne<Flights.Models.Flight>()
             .WithMany()
diff --git a/src/Services/Flight/src/Flight/Data/FlightDbContext.cs b/src/Services/Flight/src/Flight/Data/FlightDbContext.cs
index 8274430..60e6e13 100644
--- a/src/Services/Flight/src/Flight/Data/FlightDbContext.cs
+++ b/src/Services/Flight/src/Flight/Data/FlightDbContext.cs
@@ -7,7 +7,6 @@ using Microsoft.EntityFrameworkCore;
 
 namespace Flight.Data;
 
-
 public sealed class FlightDbContext : AppDbContextBase
 {
     public FlightDbContext(DbContextOptions<FlightDbContext> options, ICurrentUserProvider currentUserProvider) : base(
diff --git a/src/Services/Flight/src/Flight/Data/Migrations/20230113183335_Init.Designer.cs b/src/Services/Flight/src/Flight/Data/Migrations/20230120222458_Init.Designer.cs
similarity index 98%
rename from src/Services/Flight/src/Flight/Data/Migrations/20230113183335_Init.Designer.cs
rename to src/Services/Flight/src/Flight/Data/Migrations/20230120222458_Init.Designer.cs
index 9374273..b83b9b0 100644
--- a/src/Services/Flight/src/Flight/Data/Migrations/20230113183335_Init.Designer.cs
+++ b/src/Services/Flight/src/Flight/Data/Migrations/20230120222458_Init.Designer.cs
@@ -12,7 +12,7 @@ using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
 namespace Flight.Data.Migrations
 {
     [DbContext(typeof(FlightDbContext))]
-    [Migration("20230113183335_Init")]
+    [Migration("20230120222458_Init")]
     partial class Init
     {
         /// <inheritdoc />
@@ -64,6 +64,7 @@ namespace Flight.Data.Migrations
                         .HasColumnName("name");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
@@ -112,6 +113,7 @@ namespace Flight.Data.Migrations
                         .HasColumnName("name");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
@@ -191,6 +193,7 @@ namespace Flight.Data.Migrations
                         .HasColumnName("status");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
@@ -255,6 +258,7 @@ namespace Flight.Data.Migrations
                         .HasColumnName("type");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
diff --git a/src/Services/Flight/src/Flight/Data/Migrations/20230113183335_Init.cs b/src/Services/Flight/src/Flight/Data/Migrations/20230120222458_Init.cs
similarity index 100%
rename from src/Services/Flight/src/Flight/Data/Migrations/20230113183335_Init.cs
rename to src/Services/Flight/src/Flight/Data/Migrations/20230120222458_Init.cs
diff --git a/src/Services/Flight/src/Flight/Data/Migrations/FlightDbContextModelSnapshot.cs b/src/Services/Flight/src/Flight/Data/Migrations/FlightDbContextModelSnapshot.cs
index 3a944c1..8a46c93 100644
--- a/src/Services/Flight/src/Flight/Data/Migrations/FlightDbContextModelSnapshot.cs
+++ b/src/Services/Flight/src/Flight/Data/Migrations/FlightDbContextModelSnapshot.cs
@@ -61,6 +61,7 @@ namespace Flight.Data.Migrations
                         .HasColumnName("name");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
@@ -109,6 +110,7 @@ namespace Flight.Data.Migrations
                         .HasColumnName("name");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
@@ -188,6 +190,7 @@ namespace Flight.Data.Migrations
                         .HasColumnName("status");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
@@ -252,6 +255,7 @@ namespace Flight.Data.Migrations
                         .HasColumnName("type");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
diff --git a/src/Services/Passenger/src/Passenger/Data/Configurations/PassengerConfiguration.cs b/src/Services/Passenger/src/Passenger/Data/Configurations/PassengerConfiguration.cs
index eb787bd..9bfeff0 100644
--- a/src/Services/Passenger/src/Passenger/Data/Configurations/PassengerConfiguration.cs
+++ b/src/Services/Passenger/src/Passenger/Data/Configurations/PassengerConfiguration.cs
@@ -1,4 +1,3 @@
-using BuildingBlocks.EFCore;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Metadata.Builders;
 
@@ -12,5 +11,8 @@ public class PassengerConfiguration: IEntityTypeConfiguration<Passengers.Models.
 
         builder.HasKey(r => r.Id);
         builder.Property(r => r.Id).ValueGeneratedNever();
+
+        // // ref: https://learn.microsoft.com/en-us/ef/core/saving/concurrency?tabs=fluent-api
+        builder.Property(r => r.Version).IsConcurrencyToken();
     }
 }
diff --git a/src/Services/Passenger/src/Passenger/Data/Migrations/20230113183717_initial.Designer.cs b/src/Services/Passenger/src/Passenger/Data/Migrations/20230120222631_initial.Designer.cs
similarity index 97%
rename from src/Services/Passenger/src/Passenger/Data/Migrations/20230113183717_initial.Designer.cs
rename to src/Services/Passenger/src/Passenger/Data/Migrations/20230120222631_initial.Designer.cs
index ee01a84..4a9eca5 100644
--- a/src/Services/Passenger/src/Passenger/Data/Migrations/20230113183717_initial.Designer.cs
+++ b/src/Services/Passenger/src/Passenger/Data/Migrations/20230120222631_initial.Designer.cs
@@ -12,7 +12,7 @@ using Passenger.Data;
 namespace Passenger.Data.Migrations
 {
     [DbContext(typeof(PassengerDbContext))]
-    [Migration("20230113183717_initial")]
+    [Migration("20230120222631_initial")]
     partial class initial
     {
         /// <inheritdoc />
@@ -68,6 +68,7 @@ namespace Passenger.Data.Migrations
                         .HasColumnName("passport_number");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");
 
diff --git a/src/Services/Passenger/src/Passenger/Data/Migrations/20230113183717_initial.cs b/src/Services/Passenger/src/Passenger/Data/Migrations/20230120222631_initial.cs
similarity index 100%
rename from src/Services/Passenger/src/Passenger/Data/Migrations/20230113183717_initial.cs
rename to src/Services/Passenger/src/Passenger/Data/Migrations/20230120222631_initial.cs
diff --git a/src/Services/Passenger/src/Passenger/Data/Migrations/PassengerDbContextModelSnapshot.cs b/src/Services/Passenger/src/Passenger/Data/Migrations/PassengerDbContextModelSnapshot.cs
index 20ec96f..6612a81 100644
--- a/src/Services/Passenger/src/Passenger/Data/Migrations/PassengerDbContextModelSnapshot.cs
+++ b/src/Services/Passenger/src/Passenger/Data/Migrations/PassengerDbContextModelSnapshot.cs
@@ -65,6 +65,7 @@ namespace Passenger.Data.Migrations
                         .HasColumnName("passport_number");
 
                     b.Property<long>("Version")
+                        .IsConcurrencyToken()
                         .HasColumnType("bigint")
                         .HasColumnName("version");