diff --git a/library/build.gradle b/library/build.gradle
index bfbe72be0..8fd7d3223 100644
--- a/library/build.gradle
+++ b/library/build.gradle
@@ -86,7 +86,7 @@ dependencies {
     implementation 'org.web3j:crypto:5.0.0'
     implementation "net.java.dev.jna:jna:5.13.0@aar"
     api 'com.google.protobuf:protobuf-kotlin-lite:3.22.3'
-    api 'org.xmtp:proto-kotlin:3.31.0'
+    api 'org.xmtp:proto-kotlin:3.39.0'
 
     testImplementation 'junit:junit:4.13.2'
     androidTestImplementation 'app.cash.turbine:turbine:0.12.1'
diff --git a/library/src/androidTest/java/org/xmtp/android/library/CodecTest.kt b/library/src/androidTest/java/org/xmtp/android/library/CodecTest.kt
index 4b04fe815..5859a46ab 100644
--- a/library/src/androidTest/java/org/xmtp/android/library/CodecTest.kt
+++ b/library/src/androidTest/java/org/xmtp/android/library/CodecTest.kt
@@ -19,8 +19,8 @@ data class NumberCodec(
         authorityId = "example.com",
         typeId = "number",
         versionMajor = 1,
-        versionMinor = 1
-    )
+        versionMinor = 1,
+    ),
 ) : ContentCodec<Double> {
     override fun encode(content: Double): EncodedContent {
         return EncodedContent.newBuilder().also {
@@ -28,7 +28,7 @@ data class NumberCodec(
                 authorityId = "example.com",
                 typeId = "number",
                 versionMajor = 1,
-                versionMinor = 1
+                versionMinor = 1,
             )
             it.content = mapOf(Pair("number", content)).toString().toByteStringUtf8()
         }.build()
@@ -37,10 +37,13 @@ data class NumberCodec(
     override fun decode(content: EncodedContent): Double =
         content.content.toStringUtf8().filter { it.isDigit() || it == '.' }.toDouble()
 
+    override fun shouldPush(): Boolean = false
+
     override fun fallback(content: Double): String? {
         return "Error: This app does not support numbers."
     }
 }
+
 @RunWith(AndroidJUnit4::class)
 class CodecTest {
 
@@ -53,7 +56,7 @@ class CodecTest {
             aliceClient.conversations.newConversation(fixtures.bob.walletAddress)
         aliceConversation.send(
             content = 3.14,
-            options = SendOptions(contentType = NumberCodec().contentType)
+            options = SendOptions(contentType = NumberCodec().contentType),
         )
         val messages = aliceConversation.messages()
         assertEquals(messages.size, 1)
@@ -75,7 +78,7 @@ class CodecTest {
         val source = DecodedComposite(encodedContent = textContent)
         aliceConversation.send(
             content = source,
-            options = SendOptions(contentType = CompositeCodec().contentType)
+            options = SendOptions(contentType = CompositeCodec().contentType),
         )
         val messages = aliceConversation.messages()
         val decoded: DecodedComposite? = messages[0].content()
@@ -95,12 +98,12 @@ class CodecTest {
         val source = DecodedComposite(
             parts = listOf(
                 DecodedComposite(encodedContent = textContent),
-                DecodedComposite(parts = listOf(DecodedComposite(encodedContent = numberContent)))
-            )
+                DecodedComposite(parts = listOf(DecodedComposite(encodedContent = numberContent))),
+            ),
         )
         aliceConversation.send(
             content = source,
-            options = SendOptions(contentType = CompositeCodec().contentType)
+            options = SendOptions(contentType = CompositeCodec().contentType),
         )
         val messages = aliceConversation.messages()
         val decoded: DecodedComposite? = messages[0].content()
diff --git a/library/src/main/java/org/xmtp/android/library/Crypto.kt b/library/src/main/java/org/xmtp/android/library/Crypto.kt
index b91af0fa9..681f2d33e 100644
--- a/library/src/main/java/org/xmtp/android/library/Crypto.kt
+++ b/library/src/main/java/org/xmtp/android/library/Crypto.kt
@@ -77,26 +77,35 @@ class Crypto {
                 null
             }
         }
-    }
 
-    fun calculateMac(secret: ByteArray, message: ByteArray): ByteArray {
-        val sha256HMAC: Mac = Mac.getInstance("HmacSHA256")
-        val secretKey = SecretKeySpec(secret, "HmacSHA256")
-        sha256HMAC.init(secretKey)
-        return sha256HMAC.doFinal(message)
-    }
+        fun calculateMac(secret: ByteArray, message: ByteArray): ByteArray {
+            val sha256HMAC: Mac = Mac.getInstance("HmacSHA256")
+            val secretKey = SecretKeySpec(secret, "HmacSHA256")
+            sha256HMAC.init(secretKey)
+            return sha256HMAC.doFinal(message)
+        }
 
-    fun deriveKey(
-        secret: ByteArray,
-        salt: ByteArray,
-        info: ByteArray,
-    ): ByteArray {
-        val derivationParameters = HKDFParameters(secret, salt, info)
-        val digest = SHA256Digest()
-        val hkdfGenerator = HKDFBytesGenerator(digest)
-        hkdfGenerator.init(derivationParameters)
-        val hkdf = ByteArray(32)
-        hkdfGenerator.generateBytes(hkdf, 0, hkdf.size)
-        return hkdf
+        fun deriveKey(
+            secret: ByteArray,
+            salt: ByteArray,
+            info: ByteArray,
+        ): ByteArray {
+            val derivationParameters = HKDFParameters(secret, salt, info)
+            val digest = SHA256Digest()
+            val hkdfGenerator = HKDFBytesGenerator(digest)
+            hkdfGenerator.init(derivationParameters)
+            val hkdf = ByteArray(32)
+            hkdfGenerator.generateBytes(hkdf, 0, hkdf.size)
+            return hkdf
+        }
+
+        fun generateHmacSignature(
+            secret: ByteArray,
+            info: ByteArray,
+            message: ByteArray,
+        ): ByteArray {
+            val hkdfKey = deriveKey(secret, message, info)
+            return calculateMac(secret, hkdfKey)
+        }
     }
 }
diff --git a/library/src/main/java/org/xmtp/android/library/codecs/AttachmentCodec.kt b/library/src/main/java/org/xmtp/android/library/codecs/AttachmentCodec.kt
index 21c9e872c..f2273f14b 100644
--- a/library/src/main/java/org/xmtp/android/library/codecs/AttachmentCodec.kt
+++ b/library/src/main/java/org/xmtp/android/library/codecs/AttachmentCodec.kt
@@ -36,4 +36,6 @@ data class AttachmentCodec(override var contentType: ContentTypeId = ContentType
     override fun fallback(content: Attachment): String? {
         return "Can’t display \"${content.filename}”. This app doesn’t support attachments."
     }
+
+    override fun shouldPush(): Boolean = true
 }
diff --git a/library/src/main/java/org/xmtp/android/library/codecs/Composite.kt b/library/src/main/java/org/xmtp/android/library/codecs/Composite.kt
index 02241e6a3..d508437cc 100644
--- a/library/src/main/java/org/xmtp/android/library/codecs/Composite.kt
+++ b/library/src/main/java/org/xmtp/android/library/codecs/Composite.kt
@@ -52,6 +52,8 @@ class CompositeCodec : ContentCodec<DecodedComposite> {
         return null
     }
 
+    override fun shouldPush(): Boolean = false
+
     private fun toComposite(decodedComposite: DecodedComposite): Composite {
         return Composite.newBuilder().also {
             val content = decodedComposite.encodedContent
diff --git a/library/src/main/java/org/xmtp/android/library/codecs/ContentCodec.kt b/library/src/main/java/org/xmtp/android/library/codecs/ContentCodec.kt
index 1282e3655..732d96b44 100644
--- a/library/src/main/java/org/xmtp/android/library/codecs/ContentCodec.kt
+++ b/library/src/main/java/org/xmtp/android/library/codecs/ContentCodec.kt
@@ -67,6 +67,7 @@ interface ContentCodec<T> {
     fun encode(content: T): EncodedContent
     fun decode(content: EncodedContent): T
     fun fallback(content: T): String?
+    fun shouldPush(): Boolean
 }
 
 val id: String
diff --git a/library/src/main/java/org/xmtp/android/library/codecs/ReactionCodec.kt b/library/src/main/java/org/xmtp/android/library/codecs/ReactionCodec.kt
index f15f366d4..fbb917b7f 100644
--- a/library/src/main/java/org/xmtp/android/library/codecs/ReactionCodec.kt
+++ b/library/src/main/java/org/xmtp/android/library/codecs/ReactionCodec.kt
@@ -95,6 +95,8 @@ data class ReactionCodec(override var contentType: ContentTypeId = ContentTypeRe
             else -> null
         }
     }
+
+    override fun shouldPush(): Boolean = true
 }
 
 private class ReactionSerializer : JsonSerializer<Reaction> {
diff --git a/library/src/main/java/org/xmtp/android/library/codecs/ReadReceiptCodec.kt b/library/src/main/java/org/xmtp/android/library/codecs/ReadReceiptCodec.kt
index 6e51e77ae..c07b66d40 100644
--- a/library/src/main/java/org/xmtp/android/library/codecs/ReadReceiptCodec.kt
+++ b/library/src/main/java/org/xmtp/android/library/codecs/ReadReceiptCodec.kt
@@ -28,4 +28,6 @@ data class ReadReceiptCodec(override var contentType: ContentTypeId = ContentTyp
     override fun fallback(content: ReadReceipt): String? {
         return null
     }
+
+    override fun shouldPush(): Boolean = false
 }
diff --git a/library/src/main/java/org/xmtp/android/library/codecs/RemoteAttachmentCodec.kt b/library/src/main/java/org/xmtp/android/library/codecs/RemoteAttachmentCodec.kt
index 2fdebe0a2..29ebfce1b 100644
--- a/library/src/main/java/org/xmtp/android/library/codecs/RemoteAttachmentCodec.kt
+++ b/library/src/main/java/org/xmtp/android/library/codecs/RemoteAttachmentCodec.kt
@@ -171,4 +171,6 @@ data class RemoteAttachmentCodec(override var contentType: ContentTypeId = Conte
     override fun fallback(content: RemoteAttachment): String? {
         return "Can’t display \"${content.filename}”. This app doesn’t support attachments."
     }
+
+    override fun shouldPush(): Boolean = true
 }
diff --git a/library/src/main/java/org/xmtp/android/library/codecs/ReplyCodec.kt b/library/src/main/java/org/xmtp/android/library/codecs/ReplyCodec.kt
index f61c20400..61fe61c0a 100644
--- a/library/src/main/java/org/xmtp/android/library/codecs/ReplyCodec.kt
+++ b/library/src/main/java/org/xmtp/android/library/codecs/ReplyCodec.kt
@@ -49,6 +49,8 @@ data class ReplyCodec(override var contentType: ContentTypeId = ContentTypeReply
         return "Replied with “${content.content}” to an earlier message"
     }
 
+    override fun shouldPush(): Boolean = true
+
     private fun <Codec : ContentCodec<T>, T> encodeReply(
         codec: Codec,
         content: Any,
diff --git a/library/src/main/java/org/xmtp/android/library/codecs/TextCodec.kt b/library/src/main/java/org/xmtp/android/library/codecs/TextCodec.kt
index 378d6f060..86b15c02d 100644
--- a/library/src/main/java/org/xmtp/android/library/codecs/TextCodec.kt
+++ b/library/src/main/java/org/xmtp/android/library/codecs/TextCodec.kt
@@ -36,4 +36,6 @@ data class TextCodec(override var contentType: ContentTypeId = ContentTypeText)
     override fun fallback(content: String): String? {
         return null
     }
+
+    override fun shouldPush(): Boolean = true
 }
diff --git a/library/src/main/java/org/xmtp/android/library/messages/InvitationV1.kt b/library/src/main/java/org/xmtp/android/library/messages/InvitationV1.kt
index 347847ed7..f0cd5e57c 100644
--- a/library/src/main/java/org/xmtp/android/library/messages/InvitationV1.kt
+++ b/library/src/main/java/org/xmtp/android/library/messages/InvitationV1.kt
@@ -52,7 +52,7 @@ fun InvitationV1.createRandom(context: Context? = null): InvitationV1 {
     return InvitationV1Builder.buildFromTopic(
         topic = topic,
         context = inviteContext,
-        aes256GcmHkdfSha256 = aes256GcmHkdfSha256
+        aes256GcmHkdfSha256 = aes256GcmHkdfSha256,
     )
 }
 
@@ -68,7 +68,7 @@ fun InvitationV1.createDeterministic(
     val secret = sender.sharedSecret(
         peer = recipient,
         myPreKey = sender.preKeysList[0].publicKey,
-        isRecipient = myAddress < theirAddress
+        isRecipient = myAddress < theirAddress,
     )
 
     val addresses = arrayOf(myAddress, theirAddress)
@@ -80,12 +80,12 @@ fun InvitationV1.createDeterministic(
         addresses.joinToString(separator = ",")
     }
 
-    val topicId = Crypto().calculateMac(secret = secret, message = msg.toByteArray()).toHex()
+    val topicId = Crypto.calculateMac(secret = secret, message = msg.toByteArray()).toHex()
     val topic = Topic.directMessageV2(topicId)
-    val keyMaterial = Crypto().deriveKey(
+    val keyMaterial = Crypto.deriveKey(
         secret = secret,
         salt = "__XMTP__INVITATION__SALT__XMTP__".toByteArray(),
-        info = listOf("0").plus(addresses).joinToString(separator = "|").toByteArray()
+        info = listOf("0").plus(addresses).joinToString(separator = "|").toByteArray(),
     )
     val aes256GcmHkdfSha256 = Invitation.InvitationV1.Aes256gcmHkdfsha256.newBuilder().apply {
         this.keyMaterial = keyMaterial.toByteString()
@@ -94,7 +94,7 @@ fun InvitationV1.createDeterministic(
     return InvitationV1Builder.buildFromTopic(
         topic = topic,
         context = inviteContext,
-        aes256GcmHkdfSha256 = aes256GcmHkdfSha256
+        aes256GcmHkdfSha256 = aes256GcmHkdfSha256,
     )
 }