diff --git a/CHANGELOG.md b/CHANGELOG.md
index 210eb12..74a727d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -54,3 +54,14 @@
 ## 0.4.3
 
 - Fix bug that causes ratchets to be unable to decrypt anything after receiving a heartbeat with a completely new session
+
+## 0.5.0
+
+This version is a complete rework of omemo_dart!
+
+- Removed events from `OmemoManager`
+- Removed `OmemoSessionManager`
+- Removed serialization/deserialization code
+- Replace exceptions with errors inside a result type
+- Ratchets and trust data is now loaded and cached on demand
+- Accessing the trust manager must happen via `withTrustManager`
\ No newline at end of file
diff --git a/lib/src/errors.dart b/lib/src/errors.dart
index 8e7aecf..0925a16 100644
--- a/lib/src/errors.dart
+++ b/lib/src/errors.dart
@@ -34,3 +34,6 @@ class MalformedCiphertextError extends OmemoError {
   /// The exception that was raised while decryption.
   final Object ex;
 }
+
+/// Caused by an empty <key /> element
+class MalformedEncryptedKeyError extends OmemoError {}
diff --git a/lib/src/omemo/omemo.dart b/lib/src/omemo/omemo.dart
index 1d8232d..dd054d0 100644
--- a/lib/src/omemo/omemo.dart
+++ b/lib/src/omemo/omemo.dart
@@ -356,6 +356,14 @@ class OmemoManager {
       );
     }
 
+    // Protobuf will happily parse this and return bogus data.
+    if (key.value.isEmpty) {
+      return DecryptionResult(
+        null,
+        MalformedEncryptedKeyError(),
+      );
+    }
+
     // Check how we should process the message
     final ratchetKey =
         RatchetMapKey(stanza.bareSenderJid, stanza.senderDeviceId);
@@ -433,18 +441,23 @@ class OmemoManager {
         return DecryptionResult(null, error);
       }
 
-      final result = await _decryptAndVerifyHmac(
-        stanza.payload?.fromBase64(),
-        keyAndHmac.get<List<int>>(),
-      );
-      if (result.isType<OmemoError>()) {
-        final error = result.get<OmemoError>();
-        _log.warning('Decrypting payload failed: $error');
-
-        return DecryptionResult(
-          null,
-          error,
+      Result<OmemoError, String?> result;
+      if (stanza.payload != null) {
+        result = await _decryptAndVerifyHmac(
+          stanza.payload?.fromBase64(),
+          keyAndHmac.get<List<int>>(),
         );
+        if (result.isType<OmemoError>()) {
+          final error = result.get<OmemoError>();
+          _log.warning('Decrypting payload failed: $error');
+
+          return DecryptionResult(
+            null,
+            error,
+          );
+        }
+      } else {
+        result = const Result(null);
       }
 
       // Notify the trust manager
@@ -530,17 +543,22 @@ class OmemoManager {
         return DecryptionResult(null, error);
       }
 
-      final result = await _decryptAndVerifyHmac(
-        stanza.payload?.fromBase64(),
-        keyAndHmac.get<List<int>>(),
-      );
-      if (result.isType<OmemoError>()) {
-        final error = result.get<OmemoError>();
-        _log.warning('Failed to decrypt message: $error');
-        return DecryptionResult(
-          null,
-          error,
+      Result<OmemoError, String?> result;
+      if (stanza.payload != null) {
+        result = await _decryptAndVerifyHmac(
+          stanza.payload?.fromBase64(),
+          keyAndHmac.get<List<int>>(),
         );
+        if (result.isType<OmemoError>()) {
+          final error = result.get<OmemoError>();
+          _log.warning('Failed to decrypt message: $error');
+          return DecryptionResult(
+            null,
+            error,
+          );
+        }
+      } else {
+        result = const Result(null);
       }
 
       // If we received an empty OMEMO message, mark the ratchet as acknowledged
@@ -587,7 +605,7 @@ class OmemoManager {
 
     // Encrypt the payload, if we have any
     final List<int> payloadKey;
-    final List<int> ciphertext;
+    final List<int>? ciphertext;
     if (stanza.payload != null) {
       // Generate the key and encrypt the plaintext
       final rawKey = generateRandomBytes(32);
@@ -601,7 +619,7 @@ class OmemoManager {
       payloadKey = concat([rawKey, hmac]);
     } else {
       payloadKey = List<int>.filled(32, 0x0);
-      ciphertext = [];
+      ciphertext = null;
     }
 
     final encryptionErrors = <String, List<EncryptToJidError>>{};
@@ -942,7 +960,9 @@ class OmemoManager {
 
   /// Trust management functions
   Future<void> withTrustManager(
-      String jid, Future<void> Function(TrustManager) callback) async {
+    String jid,
+    Future<void> Function(TrustManager) callback,
+  ) async {
     await _ratchetQueue.synchronized(
       [jid],
       () => callback(_trustManager),
diff --git a/pubspec.yaml b/pubspec.yaml
index 6f7ff94..8e1d40e 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: omemo_dart
 description: An XMPP library independent OMEMO library
-version: 0.4.3
+version: 0.5.0
 homepage: https://github.com/PapaTutuWawa/omemo_dart
 publish_to: https://git.polynom.me/api/packages/PapaTutuWawa/pub