diff --git a/dom/indexedDB/ActorsChild.cpp b/dom/indexedDB/ActorsChild.cpp
index 40b1a8ad9f1e..bced12c4de6d 100644
--- a/dom/indexedDB/ActorsChild.cpp
+++ b/dom/indexedDB/ActorsChild.cpp
@@ -2053,7 +2053,7 @@ bool BackgroundDatabaseChild::DeallocPBackgroundMutableFileChild(
 }
 
 mozilla::ipc::IPCResult BackgroundDatabaseChild::RecvVersionChange(
-    const uint64_t& aOldVersion, const NullableVersion& aNewVersion) {
+    const uint64_t& aOldVersion, const Maybe<uint64_t>& aNewVersion) {
   AssertIsOnOwningThread();
 
   MaybeCollectGarbageOnIPCMessage();
@@ -2092,21 +2092,14 @@ mozilla::ipc::IPCResult BackgroundDatabaseChild::RecvVersionChange(
 
   RefPtr<Event> versionChangeEvent;
 
-  switch (aNewVersion.type()) {
-    case NullableVersion::Tnull_t:
-      versionChangeEvent =
-          IDBVersionChangeEvent::Create(kungFuDeathGrip, type, aOldVersion);
-      MOZ_ASSERT(versionChangeEvent);
-      break;
-
-    case NullableVersion::Tuint64_t:
-      versionChangeEvent = IDBVersionChangeEvent::Create(
-          kungFuDeathGrip, type, aOldVersion, aNewVersion.get_uint64_t());
-      MOZ_ASSERT(versionChangeEvent);
-      break;
-
-    default:
-      MOZ_CRASH("Should never get here!");
+  if (aNewVersion.isNothing()) {
+    versionChangeEvent =
+        IDBVersionChangeEvent::Create(kungFuDeathGrip, type, aOldVersion);
+    MOZ_ASSERT(versionChangeEvent);
+  } else {
+    versionChangeEvent = IDBVersionChangeEvent::Create(
+        kungFuDeathGrip, type, aOldVersion, aNewVersion.value());
+    MOZ_ASSERT(versionChangeEvent);
   }
 
   IDB_LOG_MARK("IndexedDB %s: Child : Firing \"versionchange\" event",
diff --git a/dom/indexedDB/ActorsChild.h b/dom/indexedDB/ActorsChild.h
index 8c113e3b5dd8..3702f67d3efc 100644
--- a/dom/indexedDB/ActorsChild.h
+++ b/dom/indexedDB/ActorsChild.h
@@ -351,7 +351,7 @@ class BackgroundDatabaseChild final : public PBackgroundIDBDatabaseChild {
       PBackgroundMutableFileChild* aActor) override;
 
   virtual mozilla::ipc::IPCResult RecvVersionChange(
-      const uint64_t& aOldVersion, const NullableVersion& aNewVersion) override;
+      const uint64_t& aOldVersion, const Maybe<uint64_t>& aNewVersion) override;
 
   virtual mozilla::ipc::IPCResult RecvInvalidate() override;
 
diff --git a/dom/indexedDB/ActorsParent.cpp b/dom/indexedDB/ActorsParent.cpp
index 95bd5dbbcb58..8dd9e1732347 100644
--- a/dom/indexedDB/ActorsParent.cpp
+++ b/dom/indexedDB/ActorsParent.cpp
@@ -6600,7 +6600,7 @@ class FactoryOp : public DatabaseOperationBase,
   nsresult SendVersionChangeMessages(DatabaseActorInfo* aDatabaseActorInfo,
                                      Database* aOpeningDatabase,
                                      uint64_t aOldVersion,
-                                     const NullableVersion& aNewVersion);
+                                     const Maybe<uint64_t>& aNewVersion);
 
   // Methods that subclasses must implement.
   virtual nsresult DatabaseOpen() = 0;
@@ -19394,7 +19394,7 @@ nsresult FactoryOp::CheckPermission(
 
 nsresult FactoryOp::SendVersionChangeMessages(
     DatabaseActorInfo* aDatabaseActorInfo, Database* aOpeningDatabase,
-    uint64_t aOldVersion, const NullableVersion& aNewVersion) {
+    uint64_t aOldVersion, const Maybe<uint64_t>& aNewVersion) {
   AssertIsOnOwningThread();
   MOZ_ASSERT(aDatabaseActorInfo);
   MOZ_ASSERT(mState == State::BeginVersionChange);
@@ -20426,7 +20426,7 @@ nsresult OpenDatabaseOp::BeginVersionChange() {
   MOZ_ASSERT(info->mMetadata != mMetadata);
   mMetadata = info->mMetadata;
 
-  NullableVersion newVersion = mRequestedVersion;
+  Maybe<uint64_t> newVersion = Some(mRequestedVersion);
 
   nsresult rv = SendVersionChangeMessages(
       info, mDatabase, mMetadata->mCommonMetadata.version(), newVersion);
@@ -21185,10 +21185,8 @@ nsresult DeleteDatabaseOp::BeginVersionChange() {
   if (gLiveDatabaseHashtable->Get(mDatabaseId, &info)) {
     MOZ_ASSERT(!info->mWaitingFactoryOp);
 
-    NullableVersion newVersion = null_t();
-
     nsresult rv =
-        SendVersionChangeMessages(info, nullptr, mPreviousVersion, newVersion);
+        SendVersionChangeMessages(info, nullptr, mPreviousVersion, Nothing());
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
diff --git a/dom/indexedDB/PBackgroundIDBDatabase.ipdl b/dom/indexedDB/PBackgroundIDBDatabase.ipdl
index 6af7a45ba5da..efe6e978f6a3 100644
--- a/dom/indexedDB/PBackgroundIDBDatabase.ipdl
+++ b/dom/indexedDB/PBackgroundIDBDatabase.ipdl
@@ -40,12 +40,6 @@ union DatabaseRequestParams
   CreateFileParams;
 };
 
-union NullableVersion
-{
-  null_t;
-  uint64_t;
-};
-
 sync protocol PBackgroundIDBDatabase
 {
   manager PBackgroundIDBFactory;
@@ -72,7 +66,7 @@ parent:
 child:
   async __delete__();
 
-  async VersionChange(uint64_t oldVersion, NullableVersion newVersion);
+  async VersionChange(uint64_t oldVersion, uint64_t? newVersion);
 
   async Invalidate();