diff --git a/res/menu/conversation_copy_session_id.xml b/res/menu/conversation_copy_session_id.xml
new file mode 100644
index 0000000000..e74d0b4c24
--- /dev/null
+++ b/res/menu/conversation_copy_session_id.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <item android:title="@string/activity_conversation_menu_copy_session_id"
+        android:id="@+id/menu_copy_session_id"
+        android:icon="@drawable/ic_content_copy_white_24dp" />
+
+</menu>
\ No newline at end of file
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 41276b0c85..a289237629 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -1860,4 +1860,6 @@
     <string name="dialog_ui_mode_option_night">Night</string>
     <string name="dialog_ui_mode_option_system_default">System default</string>
 
+    <string name="activity_conversation_menu_copy_session_id">Copy Session ID</string>
+
 </resources>
diff --git a/src/org/thoughtcrime/securesms/conversation/ConversationActivity.java b/src/org/thoughtcrime/securesms/conversation/ConversationActivity.java
index d839a90827..4a06575a30 100644
--- a/src/org/thoughtcrime/securesms/conversation/ConversationActivity.java
+++ b/src/org/thoughtcrime/securesms/conversation/ConversationActivity.java
@@ -21,6 +21,8 @@ import android.annotation.SuppressLint;
 import android.annotation.TargetApi;
 import android.content.ActivityNotFoundException;
 import android.content.BroadcastReceiver;
+import android.content.ClipData;
+import android.content.ClipboardManager;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
@@ -747,6 +749,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
       } else {
         inflater.inflate(R.menu.conversation_block, menu);
       }
+      inflater.inflate(R.menu.conversation_copy_session_id, menu);
     } else if (isGroupConversation() && !isOpenGroupOrRSSFeed) {
 //      inflater.inflate(R.menu.conversation_group_options, menu);
 
@@ -854,6 +857,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
 //    case R.id.menu_call_insecure:             handleDial(getRecipient(), false);        return true;
     case R.id.menu_unblock:                   handleUnblock();                                   return true;
     case R.id.menu_block:                     handleBlock();                                     return true;
+    case R.id.menu_copy_session_id:           handleCopySessionID();                             return true;
     case R.id.menu_view_media:                handleViewMedia();                                 return true;
     case R.id.menu_add_shortcut:              handleAddShortcut();                               return true;
     case R.id.menu_search:                    handleSearch();                                    return true;
@@ -1083,6 +1087,15 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
             }).show();
   }
 
+  private void handleCopySessionID() {
+    if (recipient.isGroupRecipient()) { return; }
+    String sessionID = recipient.getAddress().toPhoneString();
+    ClipboardManager clipboard = (ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE);
+    ClipData clip = ClipData.newPlainText("Session ID", sessionID);
+    clipboard.setPrimaryClip(clip);
+    Toast.makeText(this, R.string.copied_to_clipboard, Toast.LENGTH_SHORT).show();
+  }
+
   private void handleViewMedia() {
     Intent intent = new Intent(this, MediaOverviewActivity.class);
     intent.putExtra(MediaOverviewActivity.ADDRESS_EXTRA, recipient.getAddress());
diff --git a/src/org/thoughtcrime/securesms/jobs/PushDecryptJob.java b/src/org/thoughtcrime/securesms/jobs/PushDecryptJob.java
index 4b97762c9b..69ce6a08a6 100644
--- a/src/org/thoughtcrime/securesms/jobs/PushDecryptJob.java
+++ b/src/org/thoughtcrime/securesms/jobs/PushDecryptJob.java
@@ -834,6 +834,8 @@ public class PushDecryptJob extends BaseJob implements InjectableType {
   public long handleSynchronizeSentMediaMessage(@NonNull SentTranscriptMessage message)
       throws MmsException
   {
+    if (SessionMetaProtocol.shouldIgnoreMessage(message.getTimestamp())) { return -1; }
+
     MmsDatabase                 database        = DatabaseFactory.getMmsDatabase(context);
     Recipient                   recipients      = getSyncMessageMasterDestination(message);
     Optional<QuoteModel>        quote           = getValidatedQuote(message.getMessage().getQuote());
@@ -1002,6 +1004,7 @@ public class PushDecryptJob extends BaseJob implements InjectableType {
   public long handleSynchronizeSentTextMessage(@NonNull SentTranscriptMessage message)
       throws MmsException
   {
+    if (SessionMetaProtocol.shouldIgnoreMessage(message.getTimestamp())) { return -1; }
 
     Recipient recipient       = getSyncMessageMasterDestination(message);
     String    body            = message.getMessage().getBody().or("");
@@ -1459,7 +1462,7 @@ public class PushDecryptJob extends BaseJob implements InjectableType {
       return true;
     }
 
-    if (SessionMetaProtocol.shouldIgnoreMessage(content)) {
+    if (SessionMetaProtocol.shouldIgnoreMessage(content.getTimestamp())) {
       Log.d("Loki", "Ignoring duplicate message.");
       return true;
     }
diff --git a/src/org/thoughtcrime/securesms/loki/api/PublicChatPoller.kt b/src/org/thoughtcrime/securesms/loki/api/PublicChatPoller.kt
index 6a5ee5dad0..80b52c533e 100644
--- a/src/org/thoughtcrime/securesms/loki/api/PublicChatPoller.kt
+++ b/src/org/thoughtcrime/securesms/loki/api/PublicChatPoller.kt
@@ -5,7 +5,6 @@ import android.os.Handler
 import android.util.Log
 import nl.komponents.kovenant.Promise
 import nl.komponents.kovenant.functional.bind
-import nl.komponents.kovenant.then
 import org.thoughtcrime.securesms.ApplicationContext
 import org.thoughtcrime.securesms.crypto.IdentityKeyUtil
 import org.thoughtcrime.securesms.database.Address
@@ -34,6 +33,7 @@ import java.util.*
 class PublicChatPoller(private val context: Context, private val group: PublicChat) {
     private val handler = Handler()
     private var hasStarted = false
+    private var isPollOngoing = false
     public var isCaughtUp = false
 
     // region Convenience
@@ -186,12 +186,10 @@ class PublicChatPoller(private val context: Context, private val group: PublicCh
         }
         fun processOutgoingMessage(message: PublicChatMessage) {
             val messageServerID = message.serverID ?: return
-            val isDuplicate = DatabaseFactory.getLokiMessageDatabase(context).getMessageID(messageServerID) != null
-            if (isDuplicate) { return }
             if (message.body.isEmpty() && message.attachments.isEmpty() && message.quote == null) { return }
             val userHexEncodedPublicKey = TextSecurePreferences.getLocalNumber(context)
             val dataMessage = getDataMessage(message)
-            SessionMetaProtocol.dropFromTimestampCacheIfNeeded(dataMessage.timestamp)
+            SessionMetaProtocol.dropFromTimestampCacheIfNeeded(message.serverTimestamp)
             val transcript = SentTranscriptMessage(userHexEncodedPublicKey, message.serverTimestamp, dataMessage, dataMessage.expiresInSeconds.toLong(), Collections.singletonMap(userHexEncodedPublicKey, false))
             transcript.messageServerID = messageServerID
             if (dataMessage.quote.isPresent || (dataMessage.attachments.isPresent && dataMessage.attachments.get().size > 0) || dataMessage.previews.isPresent) {
@@ -212,6 +210,8 @@ class PublicChatPoller(private val context: Context, private val group: PublicCh
                 }
             }
         }
+        if (isPollOngoing) { return }
+        isPollOngoing = true
         val userDevices = MultiDeviceProtocol.shared.getAllLinkedDevices(userHexEncodedPublicKey)
         var uniqueDevices = setOf<String>()
         val userPrivateKey = IdentityKeyUtil.getIdentityKeyPair(context).privateKey.serialize()
@@ -249,8 +249,10 @@ class PublicChatPoller(private val context: Context, private val group: PublicCh
                 }
             }
             isCaughtUp = true
+            isPollOngoing = false
         }.fail {
             Log.d("Loki", "Failed to get messages for group chat with ID: ${group.channel} on server: ${group.server}.")
+            isPollOngoing = false
         }
     }
 
diff --git a/src/org/thoughtcrime/securesms/loki/protocol/SessionMetaProtocol.kt b/src/org/thoughtcrime/securesms/loki/protocol/SessionMetaProtocol.kt
index b4a16ed505..c3322f9a08 100644
--- a/src/org/thoughtcrime/securesms/loki/protocol/SessionMetaProtocol.kt
+++ b/src/org/thoughtcrime/securesms/loki/protocol/SessionMetaProtocol.kt
@@ -23,8 +23,7 @@ object SessionMetaProtocol {
     }
 
     @JvmStatic
-    fun shouldIgnoreMessage(content: SignalServiceContent): Boolean {
-        val timestamp = content.timestamp
+    fun shouldIgnoreMessage(timestamp: Long): Boolean {
         val shouldIgnoreMessage = timestamps.contains(timestamp)
         timestamps.add(timestamp)
         return shouldIgnoreMessage