diff --git a/server/config/database.js b/server/config/database.js
index 4d8ca55..747d3be 100644
--- a/server/config/database.js
+++ b/server/config/database.js
@@ -517,7 +517,7 @@ export async function initDatabase() {
     await db.exec('ALTER TABLE calendar_events ADD COLUMN reminder_minutes INTEGER DEFAULT NULL');
   }
   if (!(await db.columnExists('calendar_events', 'reminder_sent_at'))) {
-    await db.exec('ALTER TABLE calendar_events ADD COLUMN reminder_sent_at DATETIME DEFAULT NULL');
+    await db.exec(`ALTER TABLE calendar_events ADD COLUMN reminder_sent_at ${isPostgres ? 'TIMESTAMP' : 'DATETIME'} DEFAULT NULL`);
   }
 
   // Calendar invitations (federated calendar events that must be accepted first)