diff --git a/app/src/main/java/de/joel/zoomhelper/MainActivity.java b/app/src/main/java/de/joel/zoomhelper/MainActivity.java
index d61d7fe..b1988b2 100644
--- a/app/src/main/java/de/joel/zoomhelper/MainActivity.java
+++ b/app/src/main/java/de/joel/zoomhelper/MainActivity.java
@@ -843,6 +843,7 @@ public class MainActivity extends AppCompatActivity {
 
 
 class Attendee implements Serializable {
+    private static final long serialVersionUID = 6196688086302483907L;
     public String name;
     public String num;
 
@@ -853,6 +854,7 @@ class Attendee implements Serializable {
 }
 
 class Meeting implements Serializable {
+    private static final long serialVersionUID = 2606722401897866931L;
     public String meetingName;
     public String meetingID;
     public String meetingPWD;