diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,11 @@
 # Revision history for haskell-amqp-utils
 
+## 0.3.6.0  -- 2019-02-15
+
+* bug-fix: avoid deadlock in arbeite
+* plane: add --header option
+* rpc: log to stderr, result to stdout
+
 ## 0.3.4.0  -- 2018-07-21
 
 * bug fix: re-add exception handler
diff --git a/Network/AMQP/Utils/Helpers.hs b/Network/AMQP/Utils/Helpers.hs
--- a/Network/AMQP/Utils/Helpers.hs
+++ b/Network/AMQP/Utils/Helpers.hs
@@ -25,26 +25,27 @@
 printwithlabel :: String -> Maybe (IO ()) -> IO ()
 printwithlabel _ Nothing = return ()
 printwithlabel labl (Just i) = do
-  mapM_ putStr [" --- ", labl, ": "]
+  mapM_ (hPutStr stderr) [" --- ", labl, ": "]
   i
-  hFlush stdout
+  hFlush stderr
 
 -- | optional parameters
 printparam :: String -> Maybe String -> IO ()
-printparam labl ms = printwithlabel labl $ fmap putStrLn ms
+printparam labl ms = printwithlabel labl $ fmap (hPutStrLn stderr) ms
 
 -- | required parameters
 printparam' :: String -> String -> IO ()
 printparam' d s = printparam d (Just s)
 
 -- | head chars of body
-printbody :: (String, Maybe BL.ByteString) -> IO ()
-printbody (labl, ms) =
-  printwithlabel labl $ fmap (\s -> putStrLn "" >> BL.putStrLn s) ms
+printbody :: Handle -> (String, Maybe BL.ByteString) -> IO ()
+printbody h (labl, ms) =
+  printwithlabel labl $
+  fmap (\s -> hPutStrLn stderr "" >> BL.hPutStr h s >> hPutStrLn stderr "") ms
 
 -- | log marker
 hr :: String -> IO ()
-hr x = putStrLn hr' >> hFlush stdout
+hr x = hPutStrLn stderr hr' >> hFlush stderr
   where
     hr' = take 72 $ (take 25 hr'') ++ " " ++ x ++ " " ++ hr''
     hr'' = repeat '-'
@@ -86,9 +87,9 @@
 printopt (_, Nothing) = []
 printopt (opt, Just s) = [opt, s]
 
--- | prints header and head on STDOUT and returns cmdline options to callback
-printmsg :: (Message, Envelope) -> Maybe Int -> ZonedTime -> IO [String]
-printmsg (msg, envi) anR now = do
+-- | prints header and head on stderr and returns cmdline options to callback
+printmsg :: Handle -> (Message, Envelope) -> Maybe Int -> ZonedTime -> IO [String]
+printmsg h (msg, envi) anR now = do
   mapM_
     (uncurry printparam)
     [ ("routing key", rkey)
@@ -110,7 +111,7 @@
     , ("expiration", mexp)
     , ("delivery mode", mdelivmode)
     ]
-  printbody (label, anriss)
+  printbody h (label, anriss)
   return $
     concat
       (map
@@ -197,7 +198,7 @@
   -> String
   -> Args
   -> ThreadId
-  -> Maybe (ExitCode -> Handle -> IO ())
+  -> Maybe (ExitCode -> BL.ByteString -> IO ())
   -> IO ()
 optionalFileStuff (msg, envi) callbackoptions addi numstring a tid action = do
   path <- saveFile (tempDir a) numstring (msgBody msg)
@@ -241,15 +242,16 @@
   -> String
   -> Envelope
   -> [String]
-  -> Maybe (ExitCode -> Handle -> IO ())
+  -> Maybe (ExitCode -> BL.ByteString -> IO ())
   -> IO ()
 doProc a numstring envi (exe:args) action = do
   (_, h, _, processhandle) <-
     createProcess (proc exe args) {std_out = out, std_err = Inherit}
-  exitcode <- waitForProcess processhandle
+  sout <- mapM BL.hGetContents h
+  exitcode <- maybe 0 id (fmap BL.length sout) `seq` waitForProcess processhandle
   printparam' (numstring ++ " call returned") $ show exitcode
-  if isJust action
-    then ((fromJust action $ exitcode) (fromJust h)) >> acke envi a
+  if isJust action && isJust sout
+    then ((fromJust action $ exitcode) (fromJust sout)) >> acke envi a
     else case exitcode of
            ExitSuccess -> acke envi a
            ExitFailure _ -> reje envi a
diff --git a/Network/AMQP/Utils/Options.hs b/Network/AMQP/Utils/Options.hs
--- a/Network/AMQP/Utils/Options.hs
+++ b/Network/AMQP/Utils/Options.hs
@@ -33,6 +33,7 @@
   , connectionName :: Maybe String
   , tmpQName :: String
   , inputFile :: String
+  , outputFile :: String
   , lineMode :: Bool
   , confirm :: Bool
   , msgid :: Maybe Text
@@ -80,6 +81,7 @@
       Nothing
       ""
       "/dev/stdin"
+      "/dev/stdout"
       False
       False
       Nothing
@@ -164,12 +166,18 @@
         ["routingkey"]
         (ReqArg (\s o -> o {rKey = s}) "ROUTINGKEY")
         "AMQP routing key")
-  , ( "a"
+  , ( "ap"
     , Option
         ['f']
         ["inputfile"]
         (ReqArg (\s o -> o {inputFile = s}) "INPUTFILE")
         ("Message input file (default: " ++ (inputFile def) ++ ")"))
+  , ( "p"
+    , Option
+        ['O']
+        ["outputfile"]
+        (ReqArg (\s o -> o {outputFile = s}) "OUTPUTFILE")
+        ("Message output file (default: " ++ (outputFile def) ++ ")"))
   , ( "a"
     , Option
         ['l']
@@ -254,7 +262,7 @@
         ["exp"]
         (ReqArg (\s o -> o {msgexp = Just $ pack s}) "EXP")
         "Message Expiration")
-  , ( "a"
+  , ( "ap"
     , Option
         ['h']
         ["header"]
diff --git a/amqp-utils.cabal b/amqp-utils.cabal
--- a/amqp-utils.cabal
+++ b/amqp-utils.cabal
@@ -1,6 +1,6 @@
 name:                amqp-utils
 
-version:             0.3.4.0
+version:             0.3.6.0
 
 synopsis:            Generic Haskell AMQP Consumer
 
@@ -29,7 +29,7 @@
 
 cabal-version:       >=1.10
 
-Tested-With: GHC == 7.10.2, GHC == 8.0.2, GHC == 8.2.2, GHC == 8.4.3
+Tested-With: GHC == 7.10.2, GHC == 8.0.2, GHC == 8.2.2, GHC == 8.4.4, GHC == 8.6.3
 
 executable konsum
   main-is:             konsum.hs
diff --git a/arbeite.hs b/arbeite.hs
--- a/arbeite.hs
+++ b/arbeite.hs
@@ -3,7 +3,6 @@
 import Control.Concurrent
 import qualified Control.Exception as X
 import Control.Monad
-import qualified Data.ByteString.Lazy.Char8 as BL
 import Data.Map (singleton)
 import Data.Maybe
 import qualified Data.Text as T
@@ -16,6 +15,7 @@
 import Network.AMQP.Utils.Options
 import Paths_amqp_utils (version)
 import System.Environment
+import System.IO
 
 main :: IO ()
 main = do
@@ -67,15 +67,14 @@
   now <- getZonedTime
   callbackoptions <-
     X.catch
-      (printmsg m (anRiss a) now)
+      (printmsg stderr m (anRiss a) now)
       (\x -> X.throwTo tid (x :: X.SomeException) >> return [])
   either (\e -> printparam' "ERROR" (show (e :: X.SomeException))) return =<<
     X.try
       (optionalFileStuff m callbackoptions addi numstring a tid (Just reply))
   hr $ "END " ++ numstring
   where
-    reply e h = do
-      contents <- BL.hGetContents h
+    reply e contents = do
       void $
         publishMsg
           c
diff --git a/konsum.hs b/konsum.hs
--- a/konsum.hs
+++ b/konsum.hs
@@ -11,6 +11,7 @@
 import Network.AMQP.Utils.Options
 import Paths_amqp_utils (version)
 import System.Environment
+import System.IO
 
 main :: IO ()
 main = do
@@ -81,7 +82,7 @@
   now <- getZonedTime
   callbackoptions <-
     X.catch
-      (printmsg m (anRiss a) now)
+      (printmsg stderr m (anRiss a) now)
       (\x -> X.throwTo tid (x :: X.SomeException) >> return [])
   either
     (\e -> printparam' "ERROR" (show (e :: X.SomeException)) >> reje envi a)
diff --git a/plane.hs b/plane.hs
--- a/plane.hs
+++ b/plane.hs
@@ -16,6 +16,7 @@
 import Paths_amqp_utils (version)
 import System.Environment
 import System.Exit
+import System.IO
 
 main :: IO ()
 main = do
@@ -30,9 +31,12 @@
   (conn, chan) <- connect args
   addChannelExceptionHandler chan (X.throwTo tid)
   (q, _, _) <- declareQueue chan newQueue {queueExclusive = True}
-  ctag <- consumeMsgs chan q NoAck (rpcClientCallback tid args)
-  printparam' "consumer tag" $ T.unpack ctag
+  printparam' "input file" $ inputFile args
   message <- BL.readFile (inputFile args)
+  printparam' "output file" $ outputFile args
+  h <- openBinaryFile (outputFile args) WriteMode
+  ctag <- consumeMsgs chan q NoAck (rpcClientCallback h tid args)
+  printparam' "consumer tag" $ T.unpack ctag
   now <- getCurrentTime >>= return . floor . utcTimeToPOSIXSeconds
   hr "publishing request"
   _ <- publishMsg
@@ -45,6 +49,7 @@
       , msgCorrelationID = corrid args
       , msgExpiration = msgexp args
       , msgTimestamp = Just now
+      , msgHeaders = msgheader args
       }
   hr "waiting for answer"
   _ <- forkIO
@@ -63,14 +68,14 @@
 exceptionHandler ReceivedException = return ExitSuccess
 exceptionHandler TimeoutException = return $ ExitFailure 1
 
-rpcClientCallback :: ThreadId -> Args -> (Message, Envelope) -> IO ()
-rpcClientCallback tid a m@(_, env) = do
+rpcClientCallback :: Handle -> ThreadId -> Args -> (Message, Envelope) -> IO ()
+rpcClientCallback h tid a m@(_, env) = do
   let numstring = show $ envDeliveryTag env
   hr $ "received " ++ numstring
   now <- getZonedTime
   _ <-
     X.catch
-      (printmsg m (anRiss a) now)
+      (printmsg h m (anRiss a) now)
       (\x -> X.throwTo tid (x :: X.SomeException) >> return [])
   throwTo tid ReceivedException