diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+0.2.0
+
+* Compatible with process 1.6.
+
 0.1.6
 
 * Explicit `NoImplicitPrelude` on source files (issue #1).
diff --git a/src/Sys/CreateProcess.hs b/src/Sys/CreateProcess.hs
--- a/src/Sys/CreateProcess.hs
+++ b/src/Sys/CreateProcess.hs
@@ -27,6 +27,7 @@
 import Sys.CmdSpec(CmdSpec, AsCmdSpec(_CmdSpec), AsExecutableName(_ExecutableName), AsExecutableArguments(_ExecutableArguments), AsShellCommand(_ShellCommand), AsRawCommand(_RawCommand))
 import Sys.StdStream(StdStream, AsStdStream(_StdStream))
 import System.FilePath(FilePath)
+import System.Posix.Types(GroupID, UserID)
 import qualified System.Process as Process
 
 -- | Data type representing a process.
@@ -43,6 +44,11 @@
     Bool     
     Bool 
     Bool 
+    Bool 
+    Bool 
+    Bool
+    (Maybe GroupID) 
+    (Maybe UserID) 
   deriving (Eq, Show)
 
 -- | Types that related to @CreateProcess@.
@@ -57,16 +63,16 @@
 instance (Profunctor p, Functor f) => AsCreateProcess p f Process.CreateProcess where
   _CreateProcess =
     iso
-      (\(Process.CreateProcess s p e i o r d g c) ->
-        CreateProcess (from _CmdSpec # s) p e (from _StdStream # i) (from _StdStream # o) (from _StdStream # r) d g c)
-      (\(CreateProcess s p e i o r d g c) ->
-        Process.CreateProcess (_CmdSpec # s) p e (_StdStream # i) (_StdStream # o) (_StdStream # r) d g c)
+      (\(Process.CreateProcess s p e i o r d g c x1 x2 x3 x4 x5) ->
+        CreateProcess (from _CmdSpec # s) p e (from _StdStream # i) (from _StdStream # o) (from _StdStream # r) d g c x1 x2 x3 x4 x5)
+      (\(CreateProcess s p e i o r d g c x1 x2 x3 x4 x5) ->
+        Process.CreateProcess (_CmdSpec # s) p e (_StdStream # i) (_StdStream # o) (_StdStream # r) d g c x1 x2 x3 x4 x5)
 
 instance Functor f => AsCmdSpec (->) f CreateProcess where
   _CmdSpec =
     lens
-      (\(CreateProcess s _ _ _ _ _ _ _ _) -> s)
-      (\(CreateProcess _ p e i o r d g c) s -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess s _ _ _ _ _ _ _ _ _ _ _ _ _) -> s)
+      (\(CreateProcess _ p e i o r d g c x1 x2 x3 x4 x5) s -> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
 
 instance Applicative f => AsExecutableName (->) f CreateProcess where
   _ExecutableName =
@@ -96,8 +102,8 @@
 instance Functor f => AsWorkingDirectory (->) f CreateProcess where
   _WorkingDirectory =
     lens
-      (\(CreateProcess _ p _ _ _ _ _ _ _) -> p)
-      (\(CreateProcess s _ e i o r d g c) p -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess _ p _ _ _ _ _ _ _ _ _ _ _ _) -> p)
+      (\(CreateProcess s _ e i o r d g c x1 x2 x3 x4 x5) p -> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
 
 -- | Types that relate to an environment.
 class AsEnvironment p f s where
@@ -111,8 +117,8 @@
 instance Functor f => AsEnvironment (->) f CreateProcess where
   _Environment =
     lens
-      (\(CreateProcess _ _ e _ _ _ _ _ _) -> e)
-      (\(CreateProcess s p _ i o r d g c) e -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess _ _ e _ _ _ _ _ _ _ _ _ _ _) -> e)
+      (\(CreateProcess s p _ i o r d g c x1 x2 x3 x4 x5) e -> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
 
 -- | Types that relate to a standard input stream.
 class AsStdin p f s where
@@ -126,8 +132,8 @@
 instance Functor f => AsStdin (->) f CreateProcess where
   _Stdin =
     lens
-      (\(CreateProcess _ _ _ i _ _ _ _ _) -> i)
-      (\(CreateProcess s p e _ o r d g c) i -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess _ _ _ i _ _ _ _ _ _ _ _ _ _) -> i)
+      (\(CreateProcess s p e _ o r d g c x1 x2 x3 x4 x5) i -> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
 
 -- | Types that relate to a standard output stream.
 class AsStdout p f s where
@@ -141,8 +147,8 @@
 instance Functor f => AsStdout (->) f CreateProcess where
   _Stdout =
     lens
-      (\(CreateProcess _ _ _ _ o _ _ _ _) -> o)
-      (\(CreateProcess s p e i _ r d g c) o -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess _ _ _ _ o _ _ _ _ _ _ _ _ _) -> o)
+      (\(CreateProcess s p e i _ r d g c x1 x2 x3 x4 x5) o -> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
 
 -- | Types that relate to a standard error stream.
 class AsStderr p f s where
@@ -156,8 +162,8 @@
 instance Functor f => AsStderr (->) f CreateProcess where
   _Stderr =
     lens
-      (\(CreateProcess _ _ _ _ _ r _ _ _) -> r)
-      (\(CreateProcess s p e i o _ d g c) r -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess _ _ _ _ _ r _ _ _ _ _ _ _ _) -> r)
+      (\(CreateProcess s p e i o _ d g c x1 x2 x3 x4 x5) r -> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
 
 -- | Types that relate to closing descriptors.
 class AsCloseDescriptors p f s where
@@ -171,8 +177,8 @@
 instance Functor f => AsCloseDescriptors (->) f CreateProcess where
   _CloseDescriptors =
     lens
-      (\(CreateProcess _ _ _ _ _ _ d _ _) -> d)
-      (\(CreateProcess s p e i o r _ g c) d -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess _ _ _ _ _ _ d _ _ _ _ _ _ _) -> d)
+      (\(CreateProcess s p e i o r _ g c x1 x2 x3 x4 x5) d -> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
 
 -- | Types that relate to creating groups.
 class AsCreateGroup p f s where
@@ -186,8 +192,8 @@
 instance Functor f => AsCreateGroup (->) f CreateProcess where
   _CreateGroup =
     lens
-      (\(CreateProcess _ _ _ _ _ _ _ g _) -> g)
-      (\(CreateProcess s p e i o r d _ c) g -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess _ _ _ _ _ _ _ g _ _ _ _ _ _) -> g)
+      (\(CreateProcess s p e i o r d _ c x1 x2 x3 x4 x5) g-> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
 
 -- | Types that relate to delegating CTRL-C.
 class AsDelegateCtrlC p f s where
@@ -201,5 +207,5 @@
 instance Functor f => AsDelegateCtrlC (->) f CreateProcess where
   _DelegateCtrlC =
     lens
-      (\(CreateProcess _ _ _ _ _ _ _ _ c) -> c)
-      (\(CreateProcess s p e i o r d g _) c -> CreateProcess s p e i o r d g c)
+      (\(CreateProcess _ _ _ _ _ _ _ _ c _ _ _ _ _) -> c)
+      (\(CreateProcess s p e i o r d g _ x1 x2 x3 x4 x5) c -> CreateProcess s p e i o r d g c x1 x2 x3 x4 x5)
diff --git a/src/Sys/Exit.hs b/src/Sys/Exit.hs
--- a/src/Sys/Exit.hs
+++ b/src/Sys/Exit.hs
@@ -24,7 +24,7 @@
 import Data.Foldable(Foldable, mapM_)
 import Data.Int(Int)
 import Data.NotZero(NotZero, notZero1)
-import Data.NotZeroOr(NumberM, Number, NotZeroOrT(NotZeroOrT))
+import Data.NotZeroOr(Number, NotZeroOrT(NotZeroOrT))
 import Sys.Process as Process
 import Sys.ExitCode as ExitCode
 import qualified System.Exit as Exit
@@ -93,7 +93,7 @@
   exitWith exitSuccess
 
 type ExitCodeM f =
-  NumberM Int f
+  NotZeroOrT Int f ()
 
 exitCodeM ::
   f (Number Int) 
diff --git a/src/Sys/StdStream.hs b/src/Sys/StdStream.hs
--- a/src/Sys/StdStream.hs
+++ b/src/Sys/StdStream.hs
@@ -7,7 +7,8 @@
 , AsStdStream(..)
 , AsInherit(..)
 , AsUseHandle(..)
-, AsCreatePipe
+, AsCreatePipe(..)
+, AsNoStream(..)
 ) where
 
 import Control.Applicative(Applicative)
@@ -27,6 +28,7 @@
                              -- @Handle@ will use the default encoding
                              -- and newline translation mode (just
                              -- like @Handle@s created by @openFile@).
+  | NoStream
   deriving (Eq, Show)
 
 class AsStdStream p f s where
@@ -46,14 +48,18 @@
                Process.UseHandle h ->
                  UseHandle h
                Process.CreatePipe ->
-                 CreatePipe)
+                 CreatePipe
+               Process.NoStream ->
+                 NoStream)
       (\s -> case s of 
                Inherit ->
                  Process.Inherit
                UseHandle h ->
                  Process.UseHandle h
                CreatePipe ->
-                 Process.CreatePipe)
+                 Process.CreatePipe
+               NoStream ->
+                 Process.NoStream)
 
 class AsInherit p f s where
   _Inherit ::
@@ -73,6 +79,8 @@
                UseHandle _ ->
                  Nothing
                CreatePipe ->
+                 Nothing
+               NoStream ->
                  Nothing)
 
 class AsUseHandle p f s where
@@ -93,6 +101,8 @@
                UseHandle h ->
                  Just h
                CreatePipe ->
+                 Nothing
+               NoStream ->
                  Nothing)
 
 class AsCreatePipe p f s where
@@ -113,4 +123,28 @@
                UseHandle _ ->
                  Nothing
                CreatePipe ->
+                 Just ()
+               NoStream ->
+                 Nothing)
+
+class AsNoStream p f s where
+  _NoStream ::
+    Optic' p f s ()
+
+instance AsNoStream p f () where
+  _NoStream =
+    id
+
+instance (Choice p, Applicative f) => AsNoStream p f StdStream where
+  _NoStream =
+    prism'
+      (\() -> NoStream)
+      (\s -> case s of
+               Inherit -> 
+                 Nothing
+               UseHandle _ ->
+                 Nothing
+               CreatePipe ->
+                 Nothing
+               NoStream ->
                  Just ())
diff --git a/sys-process.cabal b/sys-process.cabal
--- a/sys-process.cabal
+++ b/sys-process.cabal
@@ -1,5 +1,5 @@
 name:               sys-process
-version:            0.1.6
+version:            0.2.0
 license:            BSD3
 license-file:       LICENSE
 author:             Tony Morris <ʇǝu˙sıɹɹoɯʇ@ןןǝʞsɐɥ> <dibblego>
@@ -29,15 +29,15 @@
                     Haskell2010
 
   build-depends:
-                      base          >= 3   && < 5
+                      base          >= 3   && <= 5
                     , mtl           >= 2.0 && < 2.3
                     , semigroups    >= 0.8
                     , semigroupoids >= 4.0
                     , bifunctors    >= 3.0
                     , lens          >= 4.0 && < 5
-                    , transformers  >= 0.3 && < 0.5
-                    , process       >= 1.2.3 && < 1.3
-                    , notzero       >= 0.0.10 && <= 0.1
+                    , transformers  >= 0.3 && < 0.6
+                    , process       >= 1.2.3 && < 1.7
+                    , notzero       >= 0.0.11 && <= 0.1
                     , filepath      >= 1.4 && < 2.0
                     , directory     >= 1.2 && < 2.0