diff --git a/common/src/main/scala/net/psforever/packet/game/PlayerStateMessageUpstream.scala b/common/src/main/scala/net/psforever/packet/game/PlayerStateMessageUpstream.scala
index 30092e62..e4a6cb52 100644
--- a/common/src/main/scala/net/psforever/packet/game/PlayerStateMessageUpstream.scala
+++ b/common/src/main/scala/net/psforever/packet/game/PlayerStateMessageUpstream.scala
@@ -6,20 +6,25 @@ import net.psforever.types.Vector3
 import scodec.Codec
 import scodec.codecs._
 
+/** PlayerStateMessageUpstream is constantly sent from the client to the server to update avatar properties.
+  *
+  * Note: seq_time appears to be used in other message definitions as well. It
+  * seems to represent a timestamp for ordering of e.g. player and weapon events.
+  */
 final case class PlayerStateMessageUpstream(avatar_guid : PlanetSideGUID,
                                             pos : Vector3,
                                             vel : Option[Vector3],
                                             unk1 : Int,
                                             aim_pitch : Int,
                                             unk2 : Int,
+                                            seq_time : Int,
                                             unk3 : Int,
-                                            unk4 : Int,
                                             is_crouching : Boolean,
+                                            unk4 : Boolean,
                                             unk5 : Boolean,
                                             unk6 : Boolean,
-                                            unk7 : Boolean,
-                                            unk8 : Int,
-                                            unk9 : Int)
+                                            unk7 : Int,
+                                            unk8 : Int)
   extends PlanetSideGamePacket {
   type Packet = PlayerStateMessageUpstream
   def opcode = GamePacketOpcode.PlayerStateMessageUpstream
@@ -34,13 +39,13 @@ object PlayerStateMessageUpstream extends Marshallable[PlayerStateMessageUpstrea
       ("unk1" | uint8L) ::
       ("aim_pitch" | uint8L) ::
       ("unk2" | uint8L) ::
-      ("unk3" | uintL(10)) ::
-      ("unk4" | uintL(3)) ::
+      ("seq_time" | uintL(10)) ::
+      ("unk3" | uintL(3)) ::
       ("is_crouching" | bool) ::
+      ("unk4" | bool) ::
       ("unk5" | bool) ::
       ("unk6" | bool) ::
-      ("unk7" | bool) ::
-      ("unk8" | uint8L) ::
-      ("unk9" | uint16L)
+      ("unk7" | uint8L) ::
+      ("unk8" | uint16L)
     ).as[PlayerStateMessageUpstream]
 }
diff --git a/common/src/test/scala/GamePacketTest.scala b/common/src/test/scala/GamePacketTest.scala
index da9aa495..2701ef80 100644
--- a/common/src/test/scala/GamePacketTest.scala
+++ b/common/src/test/scala/GamePacketTest.scala
@@ -441,21 +441,21 @@ class GamePacketTest extends Specification {
 
       "decode" in {
         PacketCoding.DecodePacket(string).require match {
-          case PlayerStateMessageUpstream(avatar_guid, pos, vel, unk1, aim_pitch, unk2, unk3, unk4, is_crouching, unk5, unk6, unk7, unk8, unk9) =>
+          case PlayerStateMessageUpstream(avatar_guid, pos, vel, unk1, aim_pitch, unk2, seq_time, unk3, is_crouching, unk4, unk5, unk6, unk7, unk8) =>
             avatar_guid mustEqual PlanetSideGUID(75)
             pos mustEqual Vector3(3694.1094f, 2735.4531f, 90.84375f)
             vel mustEqual Some(Vector3(4.375f, 2.59375f, 0.0f))
             unk1 mustEqual 10
             aim_pitch mustEqual 3
             unk2 mustEqual 0
-            unk3 mustEqual 136
-            unk4 mustEqual 0
+            seq_time mustEqual 136
+            unk3 mustEqual 0
             is_crouching mustEqual false
+            unk4 mustEqual false
             unk5 mustEqual false
             unk6 mustEqual false
-            unk7 mustEqual false
-            unk8 mustEqual 112
-            unk9 mustEqual 0
+            unk7 mustEqual 112
+            unk8 mustEqual 0
           case default =>
             ko
         }
diff --git a/pslogin/src/main/scala/WorldSessionActor.scala b/pslogin/src/main/scala/WorldSessionActor.scala
index 6fe09271..dee12365 100644
--- a/pslogin/src/main/scala/WorldSessionActor.scala
+++ b/pslogin/src/main/scala/WorldSessionActor.scala
@@ -145,7 +145,7 @@ class WorldSessionActor extends Actor with MDCContextAware {
     case KeepAliveMessage(code) =>
       sendResponse(PacketCoding.CreateGamePacket(0, KeepAliveMessage(0)))
 
-    case msg @ PlayerStateMessageUpstream(avatar_guid, pos, vel, unk1, aim_pitch, unk2, unk3, unk4, is_crouching, unk5, unk6, unk7, unk8, unk9) =>
+    case msg @ PlayerStateMessageUpstream(avatar_guid, pos, vel, unk1, aim_pitch, unk2, seq_time, unk3, is_crouching, unk4, unk5, unk6, unk7, unk8) =>
       //log.info("PlayerState: " + msg)
 
     case msg @ ChatMsg(messagetype, unk1, recipient, contents) =>