diff --git a/protocols/sacn/data.h b/protocols/sacn/data.h
index 8f0058d..dd22d52 100644
--- a/protocols/sacn/data.h
+++ b/protocols/sacn/data.h
@@ -143,7 +143,7 @@ struct data_header
   /// > for every packet sent on that universe. There is no implied relationship
   /// > between the sequence number of an E1.31 Synchronization Packet and the
   /// > sequence number of an E1.31 Data Packet on that same universe.
-  uint8_t sequence_number;
+  mutable uint8_t sequence_number;
 
   /// @brief \cite sACN 6.2.6 E1.31 Data Packet: Options
   ///
diff --git a/protocols/sacn/source.h b/protocols/sacn/source.h
index 9ab9b1f..9533053 100644
--- a/protocols/sacn/source.h
+++ b/protocols/sacn/source.h
@@ -66,16 +66,15 @@ protected:
 
 private:
     std::unordered_map <uint16_t, Universe *> universes_;
-    std::mutex universes_mutext_;
+    mutable std::mutex universes_mutext_;
 
-    /// > \cite sACN 6.2.5 E1.31 Data Packet: Sequence Number
+    /// > \cite 6.3.2 E1.31 Synchronization Packet: Sequence Number
     /// >
     /// > Sources shall maintain a sequence for each universe they transmit.
     /// > The sequence number for a universe shall be incremented by one for
     /// > every packet sent on that universe. There is no implied relationship
     /// > between the sequence number of an E1.31 Synchronization Packet and
     /// > the sequence number of an E1.31 Data Packet on that same universe.
-    std::unordered_map <uint16_t, uint8_t> data_sequences_;
     std::unordered_map <uint16_t, uint8_t> sync_sequences_;
 
     std::promise<void> discovery_exitSignal_;
diff --git a/protocols/sacn/universe.cpp b/protocols/sacn/universe.cpp
index 674d402..3b3e9fc 100644
--- a/protocols/sacn/universe.cpp
+++ b/protocols/sacn/universe.cpp
@@ -201,6 +201,12 @@ void Universe::synchronize(uint8_t sequence_number)
  */
 void Universe::sACNsend() const
 {
+  /// > \cite sACN 6.2.5 E1.31 Data Packet: Sequence Number
+  /// >
+  /// > ... The sequence number for a universe shall be incremented by one for
+  /// > every packet sent on that universe...
+  provenance_->sequence_number++;
+
   // header
   auto addrtyp = std::make_shared<ACN::DMP::address_type>();
   addrtyp->byte = 0;