diff --git a/dependencies.gradle b/dependencies.gradle
index 15e8119..0eb41e7 100644
--- a/dependencies.gradle
+++ b/dependencies.gradle
@@ -119,7 +119,7 @@ ext.Dependencies.with {
     mavenCentral.with {
         kotlinGradlePlugin = "org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVer}"
         kotlinSerializationGradlePlugin = "org.jetbrains.kotlin:kotlin-serialization:${kotlinVer}"
-        kotlinSerializationJson = "org.jetbrains.kotlinx:kotlinx-serialization-json:1.3.3"
+        kotlinSerializationJson = "org.jetbrains.kotlinx:kotlinx-serialization-json:1.4.0"
         kotlinCoroutinesCore = "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.4"
         kotlinCoroutinesTest = 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.6.4'
         kotlinTest = "org.jetbrains.kotlin:kotlin-test-junit:${kotlinVer}"
diff --git a/matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/ApiTimelineMessageContentDeserializer.kt b/matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/ApiTimelineMessageContentDeserializer.kt
index 4fd1604..324e73e 100644
--- a/matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/ApiTimelineMessageContentDeserializer.kt
+++ b/matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/ApiTimelineMessageContentDeserializer.kt
@@ -17,8 +17,8 @@ internal object ApiTimelineMessageContentDeserializer : KSerializer<ApiTimelineE
         require(decoder is JsonDecoder)
         val element = decoder.decodeJsonElement()
         return when (element.jsonObject["msgtype"]?.jsonPrimitive?.content) {
-            "m.text" -> ApiTimelineEvent.TimelineMessage.Content.Text.serializer().deserialize(decoder)
-            "m.image" -> ApiTimelineEvent.TimelineMessage.Content.Image.serializer().deserialize(decoder)
+            "m.text" -> decoder.json.decodeFromJsonElement(ApiTimelineEvent.TimelineMessage.Content.Text.serializer(), element)
+            "m.image" -> decoder.json.decodeFromJsonElement(ApiTimelineEvent.TimelineMessage.Content.Image.serializer(), element)
             else -> ApiTimelineEvent.TimelineMessage.Content.Ignored
         }
     }
diff --git a/matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/EncryptedContentDeserializer.kt b/matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/EncryptedContentDeserializer.kt
index 7fb6ba8..cd3c529 100644
--- a/matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/EncryptedContentDeserializer.kt
+++ b/matrix/services/sync/src/main/kotlin/app/dapk/st/matrix/sync/internal/request/EncryptedContentDeserializer.kt
@@ -17,8 +17,8 @@ internal object EncryptedContentDeserializer : KSerializer<ApiEncryptedContent>
         require(decoder is JsonDecoder)
         val element = decoder.decodeJsonElement()
         return when (val algorithm = element.jsonObject["algorithm"]?.jsonPrimitive?.content) {
-            "m.olm.v1.curve25519-aes-sha2" -> ApiEncryptedContent.OlmV1.serializer().deserialize(decoder)
-            "m.megolm.v1.aes-sha2" -> ApiEncryptedContent.MegOlmV1.serializer().deserialize(decoder)
+            "m.olm.v1.curve25519-aes-sha2" -> decoder.json.decodeFromJsonElement(ApiEncryptedContent.OlmV1.serializer(), element)
+            "m.megolm.v1.aes-sha2" -> decoder.json.decodeFromJsonElement(ApiEncryptedContent.MegOlmV1.serializer(), element)
             null -> ApiEncryptedContent.Unknown
             else -> throw IllegalArgumentException("Unknown algorithm : $algorithm")
         }
diff --git a/matrix/services/sync/src/test/kotlin/app/dapk/st/matrix/sync/internal/room/RoomEventsDecrypterTest.kt b/matrix/services/sync/src/test/kotlin/app/dapk/st/matrix/sync/internal/room/RoomEventsDecrypterTest.kt
index a366b48..3178ae9 100644
--- a/matrix/services/sync/src/test/kotlin/app/dapk/st/matrix/sync/internal/room/RoomEventsDecrypterTest.kt
+++ b/matrix/services/sync/src/test/kotlin/app/dapk/st/matrix/sync/internal/room/RoomEventsDecrypterTest.kt
@@ -23,6 +23,8 @@ private val AN_ENCRYPTED_ROOM_REPLY = aRoomReplyMessageEvent(
 private val A_DECRYPTED_CONTENT = DecryptedContent.TimelineText(aTimelineTextEventContent(body = A_DECRYPTED_MESSAGE_CONTENT))
 private val A_USER_CREDENTIALS = aUserCredentials()
 
+private val json = Json { encodeDefaults = true }
+
 class RoomEventsDecrypterTest {
 
     private val fakeMessageDecrypter = FakeMessageDecrypter()
@@ -67,7 +69,7 @@ class RoomEventsDecrypterTest {
     private fun givenEncryptedMessage(roomMessage: RoomEvent.Message, decryptsTo: DecryptedContent) {
         val model = roomMessage.encryptedContent!!.toModel()
         fakeMessageDecrypter.givenDecrypt(model)
-            .returns(aDecryptionSuccessResult(payload = JsonString(Json { encodeDefaults = true }.encodeToString(DecryptedContent.serializer(), decryptsTo))))
+            .returns(aDecryptionSuccessResult(payload = JsonString(json.encodeToString(DecryptedContent.serializer(), decryptsTo))))
     }
 
     private fun givenEncryptedReply(roomReply: RoomEvent.Reply, decryptsTo: DecryptedContent) {