diff --git a/src/ltlib.c b/src/ltlib.c
index 24da73ac..9e057c88 100644
--- a/src/ltlib.c
+++ b/src/ltlib.c
@@ -98,7 +98,7 @@ static float ltr_int_extrapolation_factor(int t1, int t2, int now)
   if(dt == 0){
     return 0.0f;
   }
-  float ext = (float)dt12 / dt;
+  float ext = (float)dt / dt12;
   //Should the extrapolation go further than c_EXTRAPOLATION_LIMIT
   //  times the frame interval, start to round out with asymptote
   //  of c_EXTRAPOLATION_ASYMPTOTE.
diff --git a/src/ltr_srv_slave.c b/src/ltr_srv_slave.c
index 1b1b5b49..d3e5faa5 100644
--- a/src/ltr_srv_slave.c
+++ b/src/ltr_srv_slave.c
@@ -122,6 +122,7 @@ static bool ltr_int_try_start_master(int *l_master_uplink)
   return false;
 }
 
+static linuxtrack_pose_t prev_filtered_pose;
 
 static bool ltr_int_process_message(int l_master_uplink)
 {
@@ -154,6 +155,8 @@ static bool ltr_int_process_message(int l_master_uplink)
       if(msg.pose.pose.status == RUNNING){
         //printf("PASSING TO SHM: %f %f %f\n", msg.pose.yaw, msg.pose.pitch, msg.pose.tz);
         com->full_pose = msg.pose;
+        com->full_pose.prev_pose = prev_filtered_pose;
+        prev_filtered_pose = msg.pose.pose;
       }
       com->state = msg.pose.pose.status;
       com->preparing_start = false;
diff --git a/src/xlinuxtrack9.c b/src/xlinuxtrack9.c
index 09c90ea5..08703091 100644
--- a/src/xlinuxtrack9.c
+++ b/src/xlinuxtrack9.c
@@ -176,8 +176,12 @@ PLUGIN_API int XPluginStart(char *outName,
   
   head_psi = XPLMFindDataRef("sim/graphics/view/pilots_head_psi");
   head_the = XPLMFindDataRef("sim/graphics/view/pilots_head_the");
-  
-  head_roll = XPLMFindDataRef("sim/graphics/view/field_of_view_roll_deg");
+ 
+  //New in XP11... 
+  head_roll = XPLMFindDataRef("sim/graphics/view/pilots_head_phi");
+  if(head_roll == NULL){
+    head_roll = XPLMFindDataRef("sim/graphics/view/field_of_view_roll_deg");
+  }
   view = XPLMFindDataRef("sim/graphics/view/view_type");
   
   head_x_out = XPLMRegisterDataAccessor(