diff --git a/mps/code/eventdef.h b/mps/code/eventdef.h
index fc88e8fd720..907dbf3520f 100644
--- a/mps/code/eventdef.h
+++ b/mps/code/eventdef.h
@@ -36,7 +36,7 @@
  */
 
 #define EVENT_VERSION_MAJOR  ((unsigned)1)
-#define EVENT_VERSION_MEDIAN ((unsigned)5)
+#define EVENT_VERSION_MEDIAN ((unsigned)6)
 #define EVENT_VERSION_MINOR  ((unsigned)0)
 
 
diff --git a/mps/code/format.c b/mps/code/format.c
index 351c150208a..4fd62ac5e22 100644
--- a/mps/code/format.c
+++ b/mps/code/format.c
@@ -140,6 +140,7 @@ Res FormatCreate(Format *formatReturn, Arena arena, ArgList args)
 
   format->arena = arena;
   RingInit(&format->arenaRing);
+  format->poolCount = 0;
   format->alignment = fmtAlign;
   format->headerSize = fmtHeaderSize;
   format->scan = fmtScan;
@@ -167,6 +168,7 @@ Res FormatCreate(Format *formatReturn, Arena arena, ArgList args)
 void FormatDestroy(Format format)
 {
   AVERT(Format, format);
+  AVER(format->poolCount == 0);
 
   RingRemove(&format->arenaRing);
 
@@ -229,6 +231,7 @@ Res FormatDescribe(Format format, mps_lib_FILE *stream, Count depth)
                "Format $P ($U) {\n", (WriteFP)format, (WriteFU)format->serial,
                "  arena $P ($U)\n",
                (WriteFP)format->arena, (WriteFU)format->arena->serial,
+               "  poolCount $U\n", (WriteFU)format->poolCount,
                "  alignment $W\n", (WriteFW)format->alignment,
                "  scan $F\n", (WriteFF)format->scan,
                "  skip $F\n", (WriteFF)format->skip,
diff --git a/mps/code/mpmst.h b/mps/code/mpmst.h
index 605ac21451a..2f6da006014 100644
--- a/mps/code/mpmst.h
+++ b/mps/code/mpmst.h
@@ -374,6 +374,7 @@ typedef struct mps_fmt_s {
   Serial serial;                /* from arena->formatSerial */
   Arena arena;                  /* owning arena */
   RingStruct arenaRing;         /* formats are attached to the arena */
+  Count poolCount;              /* number of pools using the format */
   Align alignment;              /* alignment of formatted objects */
   mps_fmt_scan_t scan;
   mps_fmt_skip_t skip;
diff --git a/mps/code/mps.h b/mps/code/mps.h
index bbc9dc5a505..59c59b5abc6 100644
--- a/mps/code/mps.h
+++ b/mps/code/mps.h
@@ -533,6 +533,8 @@ extern mps_res_t (mps_reserve)(mps_addr_t *, mps_ap_t, size_t);
 extern mps_bool_t (mps_commit)(mps_ap_t, mps_addr_t, size_t);
 
 extern mps_res_t mps_ap_fill(mps_addr_t *, mps_ap_t, size_t);
+
+/* mps_ap_fill_with_reservoir_permit is deprecated */			      
 extern mps_res_t mps_ap_fill_with_reservoir_permit(mps_addr_t *,
                                                    mps_ap_t,
                                                    size_t);
diff --git a/mps/code/mpsi.c b/mps/code/mpsi.c
index 3cc76ea8708..1e03a3da3cd 100644
--- a/mps/code/mpsi.c
+++ b/mps/code/mpsi.c
@@ -1175,7 +1175,7 @@ mps_res_t mps_sac_fill(mps_addr_t *p_o, mps_sac_t mps_sac, size_t size,
   AVER(p_o != NULL);
   AVER(TESTT(SAC, sac));
   arena = SACArena(sac);
-  UNUSED(has_reservoir_permit); /* FIXME */
+  UNUSED(has_reservoir_permit); /* deprecated */
 
   ArenaEnter(arena);
 
diff --git a/mps/code/pool.c b/mps/code/pool.c
index 4200643f31d..9f41560e60e 100644
--- a/mps/code/pool.c
+++ b/mps/code/pool.c
@@ -169,6 +169,11 @@ Res PoolInit(Pool pool, Arena arena, PoolClass class, ArgList args)
   /* Add initialized pool to list of pools in arena. */
   RingAppend(&globals->poolRing, &pool->arenaRing);
 
+  /* Add initialized pool to list of pools using format. */
+  if (pool->format) {
+    ++ pool->format->poolCount;
+  }
+
   return ResOK;
 
 failInit:
@@ -228,8 +233,12 @@ void PoolFinish(Pool pool)
   /* Do any class-specific finishing. */
   (*pool->class->finish)(pool);
 
-  /* Detach the pool from the arena, and unsig it. */
+  /* Detach the pool from the arena and format, and unsig it. */
   RingRemove(&pool->arenaRing);
+  if (pool->format) {
+    AVER(pool->format->poolCount > 0);
+    -- pool->format->poolCount;
+  }
   pool->sig = SigInvalid;
  
   RingFinish(&pool->segRing);
diff --git a/mps/manual/source/topic/telemetry.rst b/mps/manual/source/topic/telemetry.rst
index 0f107985c20..2c9136ce7da 100644
--- a/mps/manual/source/topic/telemetry.rst
+++ b/mps/manual/source/topic/telemetry.rst
@@ -306,14 +306,14 @@ takes the following options:
 For example, here's the result of passing the output shown above
 through :program:`mpseventtxt`::
 
-    000AE03973336E3C 002B VMCreate            vm:00000001003FC000 base:00000001003FD000 limit:00000001003FE000 
-    000AE0397333BC6D 002D VMMap               vm:00000001003FC000 base:00000001003FD000 limit:00000001003FE000 
-    000AE0397334DF9F 001A Intern              stringId:0000000000000002 string:"Reservoir" 
-    000AE0397334E0A0 001B Label               address:00000001078C85B8["Reservoir"] stringId:0000000000000002 
-    000AE03973352375 0015 PoolInit            pool:00000001003FD328 arena:00000001003FD000 poolClass:00000001078C85B8["Reservoir"] 
-    000AE039733592F9 002B VMCreate            vm:00000001003FE000 base:00000001003FF000 limit:000000010992F000 
-    000AE0397335C8B5 002D VMMap               vm:00000001003FE000 base:00000001003FF000 limit:0000000107930000 
-    000AE03973361D5A 0005 ArenaCreateVM       arena:00000001003FD000 userSize:0000000002000000 chunkSize:0000000002000000 
+    000021C9DB3812C7 0075 EventClockSync      clock:0000000000001EE3 
+    000021C9DB39E2FB 002B VMInit              vm:00007FFF5429C4B8 base:000000010BA4A000 limit:000000010BA4B000 
+    000021C9DB3A5630 002D VMMap               vm:00007FFF5429C4B8 base:000000010BA4A000 limit:000000010BA4B000 
+    000021C9DB3E6BAA 001A Intern              stringId:0000000000000002 string:"MFS" 
+    000021C9DB3E6E17 001B Label               address:000000010BA0C5D8["MFS"] stringId:0000000000000002 
+    000021C9DB3EB6F8 0044 PoolInitMFS         pool:000000010BA4A360 arena:000000010BA4A000 extendBy:0000000000001000 extendSelf:False unitSize:0000000000000030 
+    000021C9DB3EFE3B 002B VMInit              vm:00007FFF5429C3D0 base:000000010BC84000 limit:000000010CC24000 
+    000021C9DB3F33F3 002D VMMap               vm:00007FFF5429C3D0 base:000000010BC84000 limit:000000010BC85000 
 
 
 .. index::
diff --git a/mps/test/conerr/12.c b/mps/test/conerr/12.c
index a8f932114ab..139abce195b 100644
--- a/mps/test/conerr/12.c
+++ b/mps/test/conerr/12.c
@@ -4,6 +4,10 @@ TEST_HEADER
  summary = destroy a format though attached to a pool
  language = c
  link = testlib.o
+OUTPUT_SPEC
+ assert = true
+ assertfile P= format.c
+ assertcond = format->poolCount == 0
 END_HEADER
 */