diff --git a/SessionMessagingKit/Messages/Control Messages/ClosedGroupUpdate.swift b/SessionMessagingKit/Messages/Control Messages/ClosedGroupUpdate.swift
index 7b55c0c32..2e2bc18f9 100644
--- a/SessionMessagingKit/Messages/Control Messages/ClosedGroupUpdate.swift	
+++ b/SessionMessagingKit/Messages/Control Messages/ClosedGroupUpdate.swift	
@@ -126,7 +126,7 @@ public final class ClosedGroupUpdate : ControlMessage {
         return ClosedGroupUpdate(kind: kind)
     }
 
-    public override func toProto() -> SNProtoContent? {
+    public override func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
         guard let kind = kind else {
             SNLog("Couldn't construct closed group update proto from: \(self).")
             return nil
@@ -156,6 +156,8 @@ public final class ClosedGroupUpdate : ControlMessage {
             let contentProto = SNProtoContent.builder()
             let dataMessageProto = SNProtoDataMessage.builder()
             dataMessageProto.setClosedGroupUpdate(try closedGroupUpdate.build())
+            // Group context
+            try setGroupContextIfNeeded(on: dataMessageProto, using: transaction)
             contentProto.setDataMessage(try dataMessageProto.build())
             return try contentProto.build()
         } catch {
diff --git a/SessionMessagingKit/Messages/Control Messages/ExpirationTimerUpdate.swift b/SessionMessagingKit/Messages/Control Messages/ExpirationTimerUpdate.swift
index 7c2f221dc..473259c32 100644
--- a/SessionMessagingKit/Messages/Control Messages/ExpirationTimerUpdate.swift	
+++ b/SessionMessagingKit/Messages/Control Messages/ExpirationTimerUpdate.swift	
@@ -38,7 +38,7 @@ public final class ExpirationTimerUpdate : ControlMessage {
         return ExpirationTimerUpdate(duration: duration)
     }
 
-    public override func toProto() -> SNProtoContent? {
+    public override func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
         guard let duration = duration else {
             SNLog("Couldn't construct expiration timer update proto from: \(self).")
             return nil
@@ -46,6 +46,13 @@ public final class ExpirationTimerUpdate : ControlMessage {
         let dataMessageProto = SNProtoDataMessage.builder()
         dataMessageProto.setFlags(UInt32(SNProtoDataMessage.SNProtoDataMessageFlags.expirationTimerUpdate.rawValue))
         dataMessageProto.setExpireTimer(duration)
+        // Group context
+        do {
+            try setGroupContextIfNeeded(on: dataMessageProto, using: transaction)
+        } catch {
+            SNLog("Couldn't construct expiration timer update proto from: \(self).")
+            return nil
+        }
         let contentProto = SNProtoContent.builder()
         do {
             contentProto.setDataMessage(try dataMessageProto.build())
diff --git a/SessionMessagingKit/Messages/Control Messages/ReadReceipt.swift b/SessionMessagingKit/Messages/Control Messages/ReadReceipt.swift
index 5199d8980..cdce7ae1e 100644
--- a/SessionMessagingKit/Messages/Control Messages/ReadReceipt.swift	
+++ b/SessionMessagingKit/Messages/Control Messages/ReadReceipt.swift	
@@ -38,7 +38,7 @@ public final class ReadReceipt : ControlMessage {
         return ReadReceipt(timestamps: timestamps)
     }
 
-    public override func toProto() -> SNProtoContent? {
+    public override func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
         guard let timestamps = timestamps else {
             SNLog("Couldn't construct read receipt proto from: \(self).")
             return nil
diff --git a/SessionMessagingKit/Messages/Control Messages/TypingIndicator.swift b/SessionMessagingKit/Messages/Control Messages/TypingIndicator.swift
index 6d094cd62..e09de0d5d 100644
--- a/SessionMessagingKit/Messages/Control Messages/TypingIndicator.swift	
+++ b/SessionMessagingKit/Messages/Control Messages/TypingIndicator.swift	
@@ -64,7 +64,7 @@ public final class TypingIndicator : ControlMessage {
         return TypingIndicator(kind: kind)
     }
 
-    public override func toProto() -> SNProtoContent? {
+    public override func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
         guard let timestamp = sentTimestamp, let kind = kind else {
             SNLog("Couldn't construct typing indicator proto from: \(self).")
             return nil
diff --git a/SessionMessagingKit/Messages/Control Messages/Unused/NullMessage.swift b/SessionMessagingKit/Messages/Control Messages/Unused/NullMessage.swift
index a66b93192..488956883 100644
--- a/SessionMessagingKit/Messages/Control Messages/Unused/NullMessage.swift	
+++ b/SessionMessagingKit/Messages/Control Messages/Unused/NullMessage.swift	
@@ -22,7 +22,7 @@ public final class NullMessage : ControlMessage {
         return NullMessage()
     }
 
-    public override func toProto() -> SNProtoContent? {
+    public override func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
         let nullMessageProto = SNProtoNullMessage.builder()
         let paddingSize = UInt.random(in: 0..<512) // random(in:) uses the system's default random generator, which is cryptographically secure
         let padding = Data.getSecureRandomData(ofSize: paddingSize)!
diff --git a/SessionMessagingKit/Messages/Control Messages/Unused/SessionRequest.swift b/SessionMessagingKit/Messages/Control Messages/Unused/SessionRequest.swift
index 1d57a891d..52f6e0293 100644
--- a/SessionMessagingKit/Messages/Control Messages/Unused/SessionRequest.swift	
+++ b/SessionMessagingKit/Messages/Control Messages/Unused/SessionRequest.swift	
@@ -50,7 +50,7 @@ public final class SessionRequest : ControlMessage {
         return SessionRequest(preKeyBundle: preKeyBundle)
     }
 
-    public override func toProto() -> SNProtoContent? {
+    public override func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
         guard let preKeyBundle = preKeyBundle else {
             SNLog("Couldn't construct session request proto from: \(self).")
             return nil
diff --git a/SessionMessagingKit/Messages/Message.swift b/SessionMessagingKit/Messages/Message.swift
index 0f04c20db..985f9ba41 100644
--- a/SessionMessagingKit/Messages/Message.swift
+++ b/SessionMessagingKit/Messages/Message.swift
@@ -44,8 +44,15 @@ public class Message : NSObject, NSCoding { // NSObject/NSCoding conformance is
         preconditionFailure("fromProto(_:) is abstract and must be overridden.")
     }
 
-    public func toProto() -> SNProtoContent? {
-        preconditionFailure("toProto() is abstract and must be overridden.")
+    public func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
+        preconditionFailure("toProto(using:) is abstract and must be overridden.")
+    }
+
+    public func setGroupContextIfNeeded(on dataMessage: SNProtoDataMessage.SNProtoDataMessageBuilder, using transaction: YapDatabaseReadTransaction) throws {
+        guard let thread = TSThread.fetch(uniqueId: threadID!, transaction: transaction) as? TSGroupThread, thread.usesSharedSenderKeys else { return }
+        // Android needs a group context or it'll interpret the message as a one-to-one message
+        let groupProto = SNProtoGroupContext.builder(id: thread.groupModel.groupId, type: .deliver)
+        dataMessage.setGroup(try groupProto.build())
     }
     
     // MARK: General
diff --git a/SessionMessagingKit/Messages/Visible Messages/VisibleMessage.swift b/SessionMessagingKit/Messages/Visible Messages/VisibleMessage.swift
index a25735ce2..522bd5169 100644
--- a/SessionMessagingKit/Messages/Visible Messages/VisibleMessage.swift	
+++ b/SessionMessagingKit/Messages/Visible Messages/VisibleMessage.swift	
@@ -54,11 +54,7 @@ public final class VisibleMessage : Message {
         return result
     }
 
-    public override func toProto() -> SNProtoContent? {
-        preconditionFailure("Use toProto(using:) instead.")
-    }
-    
-    public func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
+    public override func toProto(using transaction: YapDatabaseReadWriteTransaction) -> SNProtoContent? {
         let proto = SNProtoContent.builder()
         var attachmentIDs = self.attachmentIDs
         let dataMessage: SNProtoDataMessage.SNProtoDataMessageBuilder
@@ -90,6 +86,13 @@ public final class VisibleMessage : Message {
         let attachmentProtos = attachments.compactMap { $0.buildProto() }
         dataMessage.setAttachments(attachmentProtos)
         // TODO: Contact
+        // Group context
+        do {
+            try setGroupContextIfNeeded(on: dataMessage, using: transaction)
+        } catch {
+            SNLog("Couldn't construct visible message proto from: \(self).")
+            return nil
+        }
         // Build
         do {
             proto.setDataMessage(try dataMessage.build())
diff --git a/SessionMessagingKit/Sending & Receiving/MessageSender.swift b/SessionMessagingKit/Sending & Receiving/MessageSender.swift
index 612c06ff2..078b19c47 100644
--- a/SessionMessagingKit/Sending & Receiving/MessageSender.swift	
+++ b/SessionMessagingKit/Sending & Receiving/MessageSender.swift	
@@ -149,13 +149,7 @@ public final class MessageSender : NSObject {
             }
         }
         // Convert it to protobuf
-        let protoOrNil: SNProtoContent?
-        if let message = message as? VisibleMessage {
-            protoOrNil = message.toProto(using: transaction) // Needed because of how TSAttachmentStream works
-        } else {
-            protoOrNil = message.toProto()
-        }
-        guard let proto = protoOrNil else { handleFailure(with: Error.protoConversionFailed, using: transaction); return promise }
+        guard let proto = message.toProto(using: transaction) else { handleFailure(with: Error.protoConversionFailed, using: transaction); return promise }
         // Serialize the protobuf
         let plaintext: Data
         do {