diff --git a/src/main/kotlin/edu/ntnu/idi/idatt/backend/bootstrap/DevDataBootstrap.kt b/src/main/kotlin/edu/ntnu/idi/idatt/backend/bootstrap/DevDataBootstrap.kt
index 78192dd..99f8561 100644
--- a/src/main/kotlin/edu/ntnu/idi/idatt/backend/bootstrap/DevDataBootstrap.kt
+++ b/src/main/kotlin/edu/ntnu/idi/idatt/backend/bootstrap/DevDataBootstrap.kt
@@ -187,7 +187,7 @@ class DevDataBootstrap(
                 ownerTeacher = teacher,
                 title = "Mysterieklubben 5A",
                 description = "Eksempelklasserom for lokal utvikling",
-                joinCode = "CLASS42",
+                joinCode = "CLASS42A",
             )
 
         val secondClassroom =
@@ -195,14 +195,14 @@ class DevDataBootstrap(
                 ownerTeacher = teacher,
                 title = "Detektivgjengen 6B",
                 description = "Eksempelklasserom",
-                joinCode = "CLASS31",
+                joinCode = "CLASS31B",
             )
         val thirdClassroom =
             seedClassroom(
                 ownerTeacher = teacher,
                 title = "Superdetektiver 4A",
                 description = "Eksempel klasserom",
-                joinCode = "CLASS21",
+                joinCode = "CLASS21A",
             )
 
         seedClassroomMembership(sampleClassroom, pupilAda, "Ada")