diff --git a/src/gen_iq_handler.erl b/src/gen_iq_handler.erl
index b815a1c19..d34db3588 100644
--- a/src/gen_iq_handler.erl
+++ b/src/gen_iq_handler.erl
@@ -164,7 +164,7 @@ process_iq(Module, Function, #iq{lang = Lang, sub_els = [El]} = IQ) ->
 	      end,
 	Module:Function(IQ#iq{sub_els = [Pkt]})
     catch error:{xmpp_codec, Why} ->
-	    Txt = xmpp:format_error(Why),
+	    Txt = xmpp:io_format_error(Why),
 	    xmpp:make_error(IQ, xmpp:err_bad_request(Txt, Lang))
     end.
 
diff --git a/src/mod_irc_connection.erl b/src/mod_irc_connection.erl
index b7b2f8e1d..593365910 100644
--- a/src/mod_irc_connection.erl
+++ b/src/mod_irc_connection.erl
@@ -418,7 +418,7 @@ handle_info({route_chan, Channel, Resource,
 	    end
     catch _:{xmpp_codec, Why} ->
 	    Err = xmpp:err_bad_request(
-		    xmpp:format_error(Why), xmpp:get_lang(Packet)),
+		    xmpp:io_format_error(Why), xmpp:get_lang(Packet)),
 	    ejabberd_router:route_error(Packet, Err)
     end,
     {next_state, StateName, StateData};
diff --git a/src/mod_mam.erl b/src/mod_mam.erl
index 92e905b6e..aed43c21e 100644
--- a/src/mod_mam.erl
+++ b/src/mod_mam.erl
@@ -491,7 +491,7 @@ process_iq(LServer, #iq{sub_els = [#mam_query{xmlns = NS}]} = IQ) ->
 process_iq(#iq{type = set, lang = Lang,
 	       sub_els = [#mam_prefs{default = undefined, xmlns = NS}]} = IQ) ->
     Why = {missing_attr, <<"default">>, <<"prefs">>, NS},
-    ErrTxt = xmpp:format_error(Why),
+    ErrTxt = xmpp:io_format_error(Why),
     xmpp:make_error(IQ, xmpp:err_bad_request(ErrTxt, Lang));
 process_iq(#iq{from = #jid{luser = LUser, lserver = LServer},
 	       to = #jid{lserver = LServer},
diff --git a/src/mod_muc_room.erl b/src/mod_muc_room.erl
index ff63ad067..67a1a2bd3 100644
--- a/src/mod_muc_room.erl
+++ b/src/mod_muc_room.erl
@@ -251,7 +251,7 @@ normal_state({route, <<"">>,
 	     try xmpp:decode_els(Packet) of
 		 Pkt -> process_normal_message(From, Pkt, StateData)
 	     catch _:{xmpp_codec, Why} ->
-		     Txt = xmpp:format_error(Why),
+		     Txt = xmpp:io_format_error(Why),
 		     Err = xmpp:err_bad_request(Txt, Lang),
 		     ejabberd_router:route_error(Packet, Err),
 		     StateData
@@ -329,7 +329,7 @@ normal_state({route, <<"">>,
 		end
 	end
     catch _:{xmpp_codec, Why} ->
-	    ErrTxt = xmpp:format_error(Why),
+	    ErrTxt = xmpp:io_format_error(Why),
 	    Err = xmpp:err_bad_request(ErrTxt, Lang),
 	    ejabberd_router:route_error(IQ0, Err)
     end;
diff --git a/src/mod_multicast.erl b/src/mod_multicast.erl
index e10315b7a..7b772521d 100644
--- a/src/mod_multicast.erl
+++ b/src/mod_multicast.erl
@@ -240,7 +240,7 @@ handle_iq(Packet, State) ->
 	end
     catch _:{xmpp_codec, Why} ->
 	    Lang = xmpp:get_lang(Packet),
-	    Err = xmpp:err_bad_request(xmpp:format_error(Why), Lang),
+	    Err = xmpp:err_bad_request(xmpp:io_format_error(Why), Lang),
 	    ejabberd_router:route_error(Packet, Err)
     end.
 
diff --git a/src/mod_privacy.erl b/src/mod_privacy.erl
index c4a1c471d..64ae9620e 100644
--- a/src/mod_privacy.erl
+++ b/src/mod_privacy.erl
@@ -353,7 +353,7 @@ process_lists_set(#iq{from = #jid{luser = LUser, lserver = LServer} = From,
 		      lang = Lang} = IQ, Name, Items) ->
     case catch lists:map(fun decode_item/1, Items) of
 	{error, Why} ->
-	    Txt = xmpp:format_error(Why),
+	    Txt = xmpp:io_format_error(Why),
 	    xmpp:make_error(IQ, xmpp:err_bad_request(Txt, Lang));
 	List ->
 	    case set_list(LUser, LServer, Name, List) of
diff --git a/src/mod_privilege.erl b/src/mod_privilege.erl
index 6ba061a53..dab7a619b 100644
--- a/src/mod_privilege.erl
+++ b/src/mod_privilege.erl
@@ -292,7 +292,7 @@ forward_message(#message{to = To} = Msg) ->
 		    Err = xmpp:err_bad_request(Txt, Lang),
 		    ejabberd_router:route_error(Msg, Err)
 	    catch _:{xmpp_codec, Why} ->
-		    Txt = xmpp:format_error(Why),
+		    Txt = xmpp:io_format_error(Why),
 		    Err = xmpp:err_bad_request(Txt, Lang),
 		    ejabberd_router:route_error(Msg, Err)
 	    end;
diff --git a/src/mod_proxy65_service.erl b/src/mod_proxy65_service.erl
index 4a4729dcf..fb34ba554 100644
--- a/src/mod_proxy65_service.erl
+++ b/src/mod_proxy65_service.erl
@@ -189,12 +189,12 @@ process_bytestreams(#iq{type = set, lang = Lang,
 			sub_els = [#bytestreams{sid = SID}]} = IQ)
   when SID == <<"">> orelse size(SID) > 128 ->
     Why = {bad_attr_value, <<"sid">>, <<"query">>, ?NS_BYTESTREAMS},
-    Txt = xmpp:format_error(Why),
+    Txt = xmpp:io_format_error(Why),
     xmpp:make_error(IQ, xmpp:err_bad_request(Txt, Lang));
 process_bytestreams(#iq{type = set, lang = Lang, 
 			sub_els = [#bytestreams{activate = undefined}]} = IQ) ->
     Why = {missing_cdata, <<"">>, <<"activate">>, ?NS_BYTESTREAMS},
-    Txt = xmpp:format_error(Why),
+    Txt = xmpp:io_format_error(Why),
     xmpp:make_error(IQ, xmpp:err_jid_malformed(Txt, Lang));
 process_bytestreams(#iq{type = set, lang = Lang, from = InitiatorJID, to = To,
 			sub_els = [#bytestreams{activate = TargetJID,