diff --git a/timetracker.Server/Data/Migrations/20260624210436_AddTenantBranding.cs b/timetracker.Server/Data/Migrations/20260624210436_AddTenantBranding.cs
index 897b5eb..7751ae7 100644
--- a/timetracker.Server/Data/Migrations/20260624210436_AddTenantBranding.cs
+++ b/timetracker.Server/Data/Migrations/20260624210436_AddTenantBranding.cs
@@ -1,4 +1,4 @@
-using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
 
@@ -13,7 +13,6 @@ namespace timetracker.Data.Migrations
             migrationBuilder.AddColumn<bool>(
                 name: "IsTenantAdmin",
                 table: "Users",
-                type: "INTEGER",
                 nullable: false,
                 defaultValue: false);
 
diff --git a/timetracker.Server/Program.cs b/timetracker.Server/Program.cs
index 2eb20e7..e3c82c6 100644
--- a/timetracker.Server/Program.cs
+++ b/timetracker.Server/Program.cs
@@ -195,6 +195,44 @@ using (var scope = app.Services.CreateScope())
     }
 
     await db.Database.MigrateAsync();
+
+    if (dbProvider.Equals("PostgreSQL", StringComparison.OrdinalIgnoreCase))
+    {
+        try
+        {
+            var conn = db.Database.GetDbConnection();
+            if (conn.State != System.Data.ConnectionState.Open)
+            {
+                await conn.OpenAsync();
+            }
+
+            // Check if column IsTenantAdmin in Users table is of type integer
+            using (var cmdCheckType = conn.CreateCommand())
+            {
+                cmdCheckType.CommandText = @"
+                    SELECT data_type 
+                    FROM information_schema.columns 
+                    WHERE table_name = 'Users' AND column_name = 'IsTenantAdmin';";
+                var dataType = await cmdCheckType.ExecuteScalarAsync() as string;
+                if (dataType != null && dataType.Equals("integer", StringComparison.OrdinalIgnoreCase))
+                {
+                    // Alter the column type to boolean
+                    using (var cmdAlterType = conn.CreateCommand())
+                    {
+                        cmdAlterType.CommandText = @"
+                            ALTER TABLE ""Users"" 
+                            ALTER COLUMN ""IsTenantAdmin"" TYPE boolean 
+                            USING (""IsTenantAdmin"" <> 0);";
+                        await cmdAlterType.ExecuteNonQueryAsync();
+                    }
+                }
+            }
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"Fehler beim Konvertieren der IsTenantAdmin-Spalte in PostgreSQL: {ex.Message}");
+        }
+    }
 }
 
 var forwardedHeadersOptions = new ForwardedHeadersOptions