diff --git a/hyperx.nimble b/hyperx.nimble
index d7178b0..6dfe2ee 100644
--- a/hyperx.nimble
+++ b/hyperx.nimble
@@ -9,7 +9,7 @@ skipDirs = @["tests"]
 
 requires "nim >= 2.0.0"
 #requires "hpack >= 0.2.0"
-requires "https://github.com/nitely/nim-hpack#update_size"
+requires "https://github.com/nitely/nim-hpack#head"
 
 task test, "Test":
   exec "nim c -r src/hyperx/utils.nim"
diff --git a/src/hyperx/client.nim b/src/hyperx/client.nim
index de4d91e..3dfa80a 100644
--- a/src/hyperx/client.nim
+++ b/src/hyperx/client.nim
@@ -125,6 +125,7 @@ type
   MsgData = object
     frm: Frame
   Stream = object
+    # XXX: add body stream, if set stream data through it
     id: StreamId
     state: StreamState
     msgs: QueueAsync[MsgData]
@@ -341,6 +342,8 @@ proc read(client: ClientContext, frm: Frame) {.async.} =
   payloadLen -= paddingLen
   check isValidSize(frm, payloadLen), newConnError(errFrameSizeError)
   if payloadLen > 0:
+    # XXX recv into Stream.bodyStream if typ is frmtData
+    # XXX recv in chunks and discard if stream does not exists
     frm.grow payloadLen
     let payloadRln = await client.sock.recvInto(
       frm.rawPayloadBytesPtr, payloadLen
@@ -378,12 +381,9 @@ proc handshake(client: ClientContext) {.async.} =
   # XXX: allow sending some params
   let sid = client.openMainStream()
   doAssert sid == frmSidMain.StreamId
-  var frm = newFrame()
-  frm.setTyp frmtSettings
-  frm.setSid frmSidMain
+  var frm = newSettingsFrame()
   frm.addSetting frmsEnablePush, stgDisablePush
   frm.addSetting frmsInitialWindowSize, stgMaxWindowSize
-  frm.setPayloadLen frm.payload.len.FrmPayloadLen
   var blob = newSeqOfCap[byte](preface.len+frm.len)
   blob.add preface
   blob.add frm.s
@@ -433,7 +433,6 @@ const connFrmAllowed = {
 }
 
 proc consumeMainStream(client: ClientContext, frm: Frame) {.async.} =
-  # XXX process settings, window updates, etc
   case frm.typ
   of frmtWindowUpdate:
     check frm.payload.len > 0, newConnError(errProtocolError)
@@ -462,8 +461,8 @@ proc consumeMainStream(client: ClientContext, frm: Frame) {.async.} =
         discard
       else:
         # ignore unknown setting
-        debugInfo "unknown setting recived"
-    # XXX send ack
+        debugInfo "unknown setting received"
+    await client.write newSettingsFrame()
   of frmtPing: discard
   of frmtGoAway: discard
   else:
diff --git a/src/hyperx/frame.nim b/src/hyperx/frame.nim
index d2b8b3c..6012af8 100644
--- a/src/hyperx/frame.nim
+++ b/src/hyperx/frame.nim
@@ -238,11 +238,20 @@ func newWindowUpdateFrame*(
   result.setPayloadLen frmWindowUpdateSize.FrmPayloadLen
   result.s.assignAt(frmHeaderSize, increment.uint32)
 
+func newSettingsFrame*(ack = false): Frame {.inline, raises: [].} =
+  result = newFrame()
+  result.setTyp frmtSettings
+  result.setSid frmSidMain
+  if ack:
+    result.flags.incl frmfAck
+
 func addSetting*(
   frm: Frame,
   id: FrmSetting,
   value: uint32
 ) {.inline, raises: [].} =
+  doAssert frm.typ == frmtSettings
+  doAssert frmfAck notin frm.flags
   let i = frm.len
   frm.grow frmSettingsSize
   frm.setPayloadLen frm.payload.len.FrmPayloadLen
diff --git a/tests/testclient.nim b/tests/testclient.nim
index 9bafa76..6d7dd3d 100644
--- a/tests/testclient.nim
+++ b/tests/testclient.nim
@@ -289,9 +289,10 @@ testAsync "header table size setting is applied":
     ":path: /foo\r\L" &
     ":authority: foo.bar\r\L"
   # XXX reqs[2] window size update
-  doAssert reqs[3].frm.sid.int == 3
-  doAssert reqs[3].frm.typ == frmtHeaders
-  doAssert reqs[3].payload ==
+  # XXX reqs[3] ack window size update
+  doAssert reqs[4].frm.sid.int == 3
+  doAssert reqs[4].frm.typ == frmtHeaders
+  doAssert reqs[4].payload ==
     ":method: GET\r\L" &
     ":scheme: https\r\L" &
     ":path: /bar\r\L" &