diff -Nur -Xfreecivdiff.ignore freeciv-cvs/client/packhand.c freeciv-patched/client/packhand.c
--- freeciv-cvs/client/packhand.c	2003-07-24 16:57:16.000000000 +0100
+++ freeciv-patched/client/packhand.c	2003-07-24 16:59:04.000000000 +0100
@@ -76,6 +76,16 @@
 static int *reports_thaw_requests = NULL;
 static int reports_thaw_requests_size = 0;
 
+/* Keeps track of whether we are in a turn update or not. This is used by
+ * the city packet handling routines to decide whether to update improvement
+ * effects immediately on receiving new improvements, or to defer the update
+ * until the start of the turn. */
+static enum {
+  EU_BEFORE_YEAR,
+  EU_UPDATE_DEFERRED,
+  EU_WITHIN_YEAR
+} effect_update_state = EU_BEFORE_YEAR;
+
 /**************************************************************************
   Unpackage the unit information into a newly allocated unit structure.
 **************************************************************************/
@@ -120,6 +130,9 @@
   char msg[MAX_LEN_MSG];
   char *s_capability = aconnection.capability;
 
+  /* Defer all effect updates until the start of the first year */
+  effect_update_state = EU_BEFORE_YEAR;
+
   sz_strlcpy(aconnection.capability, packet->capability);
   close_connection_dialog();
 
@@ -271,15 +284,33 @@
 static void try_update_effects(bool need_update)
 {
   if (need_update) {
-    /* nothing yet... */
+    if (effect_update_state == EU_WITHIN_YEAR) {
+      update_all_effects();
+    } else {
+      effect_update_state = EU_UPDATE_DEFERRED;
+    }
   }
 }
 
 /**************************************************************************
+  If any effect updates were deferred by try_update_effects(), update them
+**************************************************************************/
+static void do_deferred_effect_updates(void)
+{
+  if (effect_update_state == EU_UPDATE_DEFERRED) {
+    update_all_effects();
+  }
+  effect_update_state = EU_WITHIN_YEAR;
+}
+
+/**************************************************************************
 ...
 **************************************************************************/
 void handle_game_state(struct packet_generic_integer *packet)
 {
+  /* If any effect updates were deferred, update effects now */
+  do_deferred_effect_updates();
+
   if (get_client_state() == CLIENT_SELECT_RACE_STATE
       && packet->value == CLIENT_GAME_RUNNING_STATE
       && game.player_ptr->nation == NO_NATION_SELECTED) {
@@ -467,6 +498,8 @@
            pcity->owner==game.player_idx && popup_new_cities) 
           || packet->diplomat_investigate;
 
+  try_update_effects(need_effect_update);
+
   if (city_is_new && !city_has_changed_owner) {
     agents_city_new(pcity);
   } else {
@@ -474,8 +507,6 @@
   }
 
   handle_city_packet_common(pcity, city_is_new, popup, packet->diplomat_investigate);
-
-  try_update_effects(need_effect_update);
 }
 
 /**************************************************************************
@@ -663,6 +694,8 @@
 	pcity->city_map[x][y] = C_TILE_EMPTY;
   } /* Dumb values */
 
+  try_update_effects(need_effect_update);
+
   if (city_is_new && !city_has_changed_owner) {
     agents_city_new(pcity);
   } else {
@@ -675,8 +708,6 @@
   if (update_descriptions && tile_visible_mapcanvas(pcity->x,pcity->y)) {
     queue_mapview_update(UPDATE_CITY_DESCRIPTIONS);
   }
-
-  try_update_effects(need_effect_update);
 }
 
 /**************************************************************************
@@ -684,6 +715,9 @@
 **************************************************************************/
 void handle_new_year(struct packet_new_year *ppacket)
 {
+  /* If any effect updates were deferred, update effects now */
+  do_deferred_effect_updates();
+
   game.year = ppacket->year;
   /*
    * The turn was increased in handle_before_new_year()
@@ -722,6 +756,9 @@
 **************************************************************************/
 void handle_before_new_year(void)
 {
+  /* Defer all effect updates until the start of the year */
+  effect_update_state = EU_BEFORE_YEAR;
+
   clear_notify_window();
   /*
    * The local idea of the game turn is increased here since the
@@ -740,6 +777,9 @@
 **************************************************************************/
 void handle_start_turn(void)
 {
+  /* If any effect updates were deferred, update effects now */
+  do_deferred_effect_updates();
+
   agents_start_turn();
   non_ai_unit_focus = FALSE;