diff --git a/db/migrations/20251005183109_calendar_add_fields.php b/db/migrations/20251005183109_calendar_add_fields.php
new file mode 100644
index 000000000..d5375fcd2
--- /dev/null
+++ b/db/migrations/20251005183109_calendar_add_fields.php
@@ -0,0 +1,83 @@
+<?php
+declare(strict_types=1);
+
+use Phinx\Migration\AbstractMigration;
+
+final class CalendarAddFields extends AbstractMigration
+{
+    public function up(): void
+    {
+        if($this->getEnvironment() == "thetool") {
+            $table = $this->table('Calendar');
+            if (!$table->hasColumn('calendar_name')) {
+                $table->addColumn('calendar_name', 'string', [
+                    'limit' => 255,
+                    'null'  => true,
+                    'after' => 'user_id',
+                ]);
+            }
+            if (!$table->hasColumn('calendar_firstname')) {
+                $table->addColumn('calendar_firstname', 'string', [
+                    'limit' => 100,
+                    'null'  => true,
+                    'after' => 'calendar_name',
+                ]);
+            }
+            if (!$table->hasColumn('calendar_lastname')) {
+                $table->addColumn('calendar_lastname', 'string', [
+                    'limit' => 100,
+                    'null'  => true,
+                    'after' => 'calendar_firstname',
+                ]);
+            }
+            if (!$table->hasColumn('calendar_email')) {
+                $table->addColumn('calendar_email', 'string', [
+                    'limit' => 255,
+                    'null'  => true,
+                    'after' => 'calendar_name', // wie in deinem SQL
+                ]);
+            }
+            if ($table->hasColumn('user_id')) {
+                $table->changeColumn('user_id', 'integer', [
+                    'null'    => true,
+                    'default' => null,
+                ]);
+            }
+            if ($table->hasColumn('microsoft_id')) {
+                $table->changeColumn('microsoft_id', 'text', [
+                    'null'      => true,
+                    'encoding'  => 'utf8mb4',
+                    'collation' => 'utf8mb4_unicode_ci',
+                ]);
+            }
+            $table->update();
+        }
+        
+        if($this->getEnvironment() == "addressdb") {
+          
+        }
+    }
+
+    public function down(): void
+    {
+        if($this->getEnvironment() == "thetool") {
+            $table = $this->table('Calendar');
+            if ($table->hasColumn('calendar_email')) {
+                $table->removeColumn('calendar_email');
+            }
+            if ($table->hasColumn('calendar_lastname')) {
+                $table->removeColumn('calendar_lastname');
+            }
+            if ($table->hasColumn('calendar_firstname')) {
+                $table->removeColumn('calendar_firstname');
+            }
+            if ($table->hasColumn('calendar_name')) {
+                $table->removeColumn('calendar_name');
+            }
+        }
+        
+        if($this->getEnvironment() == "addressdb") {
+          
+        }
+    }
+}