diff --git a/desk/app/channels-server.hoon b/desk/app/channels-server.hoon
index 47a7bb4f49..acd012d44a 100644
--- a/desk/app/channels-server.hoon
+++ b/desk/app/channels-server.hoon
@@ -16,7 +16,7 @@
   |%
   +$  card  card:agent:gall
   +$  current-state
-    $:  %2
+    $:  %3
         =v-channels:c
     ==
   --
@@ -86,12 +86,19 @@
   =+  !<(old=versioned-state vase)
   =?  old  ?=(%0 -.old)  (state-0-to-1 old)
   =?  old  ?=(%1 -.old)  (state-1-to-2 old)
-  ?>  ?=(%2 -.old)
+  =?  cor  ?=(%2 -.old)  (emit %pass /trim %agent [our.bowl %chat] %poke %chat-trim !>(~))
+  =?  old  ?=(%2 -.old)  (state-2-to-3 old)
+  ?>  ?=(%3 -.old)
   =.  state  old
   inflate-io
   ::
-  +$  versioned-state  $%(state-2 state-1 state-0)
-  +$  state-2  current-state
+  +$  versioned-state  $%(state-3 state-2 state-1 state-0)
+  +$  state-3  current-state
+  +$  state-2  [%2 =v-channels:c]
+  ++  state-2-to-3
+    |=  old=state-2
+    ^-  state-3
+    [%3 +.old]
   ::
   ::  %1 to %2
   ::
@@ -204,17 +211,15 @@
   ^+  cor
   =.  cor
     %-  emil
-    %-  turn  :_  |=(=note:agent:gall [%pass /migrate note])
-    ^-  (list note:agent:gall)
-    :~  [%agent [our.bowl %diary] %poke %diary-migrate-server !>(~)]
-        [%agent [our.bowl %heap] %poke %heap-migrate-server !>(~)]
-        [%agent [our.bowl %chat] %poke %chat-migrate-server !>(~)]
+    :~  [%pass /migrate %agent [our.bowl %diary] %poke %diary-migrate-server !>(~)]
+        [%pass /migrate %agent [our.bowl %heap] %poke %heap-migrate-server !>(~)]
+        [%pass /migrate %agent [our.bowl %chat] %poke %chat-migrate-server !>(~)]
         ::NOTE  we do these here and not in /app/channels, because it's
         ::      important that the server migration happens first, so that
         ::      the client migration may successfully establish subscriptions.
-        [%agent [our.bowl %diary] %poke %diary-migrate !>(~)]
-        [%agent [our.bowl %heap] %poke %heap-migrate !>(~)]
-        [%agent [our.bowl %chat] %poke %chat-migrate !>(~)]
+        [%pass /migrate %agent [our.bowl %diary] %poke %diary-migrate !>(~)]
+        [%pass /migrate %agent [our.bowl %heap] %poke %heap-migrate !>(~)]
+        [%pass /migrate/final %agent [our.bowl %chat] %poke %chat-migrate !>(~)]
     ==
   inflate-io
 ::
@@ -325,6 +330,19 @@
       %-  (slog 'channels-server: migration poke failure' >wire< u.p.sign)
       cor
     ==
+      [%migrate %final ~]
+    ?+  -.sign  !!
+        %poke-ack
+      ?~  p.sign
+      (emit %pass /trim %agent [our.bowl %chat] %poke %chat-trim !>(~))
+      %-  (slog 'channels-server: migration poke failure' >wire< u.p.sign)
+      cor
+    ==
+      [%trim ~]
+    ?+  -.sign  !!
+        %poke-ack
+      cor
+    ==
   ==
 ::
 ++  watch-groups  (safe-watch /groups [our.bowl %groups] /groups)
diff --git a/desk/app/chat.hoon b/desk/app/chat.hoon
index b29883c7fb..d67bc3d886 100644
--- a/desk/app/chat.hoon
+++ b/desk/app/chat.hoon
@@ -518,6 +518,9 @@
     ?>  from-self
     =+  !<(flag=[ship term] vase)
     (refs:migrate flag)
+      %chat-trim
+    ?>  from-self
+    trim:migrate
   ::  backwards compatibility
   ::
       %dm-rsvp
@@ -902,6 +905,51 @@
       !>(`a-channels:d`[%channel [%chat flag] %post u.command])
     `[%pass /migrate %agent [our.bowl %channels] %poke cage]
   ::
+  ++  trim
+    =-  =.  old-chats  -  cor
+    ^-  (map flag:two:old:c chat:two:old:c)
+    %-  ~(run by old-chats)
+    |=  old-chat=chat:two:old:c
+    =/  citations=(set [ship time])
+      %-  sy
+      ^-  (list [ship time])
+      %-  zing
+      ^-  (list (list [ship time]))
+      %+  murn  (tap:on:writs:old wit.pact.old-chat)
+      |=  [=time =writ:old]
+      ^-  (unit (list [ship ^time]))
+      ::  return citer message and cited message
+      ?.  =(our.bowl author.writ)  ~
+      =/  cite-targets=(list [ship ^time])
+        ?.  ?=(%story -.content.writ)  ~
+        %+  murn  p.p.content.writ
+        |=  =block:old
+        ^-  (unit [ship ^time])
+        ?.  ?=([%cite %chan [%chat *] *] block)  ~
+        ?.  ?=([%msg @ @ ~] wer.cite.block)  ~
+        =/  who  (slaw %p i.t.wer.cite.block)
+        ?~  who  ~
+        =/  tim  (slaw %ud i.t.t.wer.cite.block)
+        ?~  tim  ~
+        `[u.who u.tim]
+      ?~  cite-targets
+        ~
+      `[id.writ cite-targets]
+    %=  old-chat
+      log  ~
+      dex.pact
+        %-  malt
+        %+  murn  ~(tap by dex.pact.old-chat)
+        |=  [=id:old =time]
+        ?.  (~(has in citations) id)  ~
+        `[id time]
+      wit.pact
+        %-  malt
+        %+  murn  (tap:on:writs:old wit.pact.old-chat)
+        |=  [=time =writ:old]
+        ?.  (~(has in citations) id.writ)  ~
+        `[time writ]
+    ==
   ++  convert-pin
     |=  =whom:t
     ^-  whom:u