diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,8 +4,13 @@
 CHANGELOG](http://keepachangelog.com/). This project adheres to [Semantic
 Versioning](http://semver.org/).
 
-## [0.3] - 2015-5-25
+## [0.4] - 2015-08-06
 ### Added
+- Support for stack.
+- `CoSerial` instances.
+
+## [0.3] - 2015-05-25
+### Added
 - Serial instance for `Map`.
 - `zipLogic` for *zipping* instances. Thanks to Roman Cheplyaka
   [@feuerbach](https://github.com/feuerbach).
@@ -13,18 +18,19 @@
 ### Fixed
 - Compatibility with GHC < 7.10.
 
-## [0.2] - 2015-4-28
+## [0.2] - 2015-04-28
 ### Changed
 - General renaming to, hopefully, make functions more clear.
 ### Fixed
 - Series don't repeat elements anymore. Kudos to Roman Cheplyaka for
   reporting this issue.
 
-## [0.1] - 2015-4-27
+## [0.1] - 2015-04-27
 ### Added
 - Initial set of utilities for creating `ByteString` and `Text` `Series`.
 - `Serial` `ByteString` and `Text` instances.
 
+[0.4]: https://github.com/jdnavarro/smallcheck-series/compare/v0.3...v0.4
 [0.3]: https://github.com/jdnavarro/smallcheck-series/compare/v0.2...v0.3
 [0.2]: https://github.com/jdnavarro/smallcheck-series/compare/v0.1...v0.2
 [0.1]: https://github.com/jdnavarro/smallcheck-series/compare/49b5b0...v0.1
diff --git a/Test/SmallCheck/Series/Instances.hs b/Test/SmallCheck/Series/Instances.hs
--- a/Test/SmallCheck/Series/Instances.hs
+++ b/Test/SmallCheck/Series/Instances.hs
@@ -27,6 +27,7 @@
 import qualified Data.ByteString.Lazy as BL
 import qualified Data.Text as T
 import qualified Data.Text.Lazy as TL
+import Data.Map
 import qualified Data.Map as Map
 import Test.SmallCheck.Series
 
@@ -38,15 +39,54 @@
 
 instance Monad m => Serial m B.ByteString where
     series = Series.ByteString.replicateA
+instance Monad m => CoSerial m B.ByteString where
+    coseries rs =
+        alts0 rs >>- \y ->
+        alts2 rs >>- \f ->
+            return $ \bs -> case B.uncons bs of
+                Nothing -> y
+                Just (b,bs') -> f (B.singleton b) bs'
 
 instance Monad m => Serial m BL.ByteString where
     series = Series.ByteString.Lazy.replicateA
+instance Monad m => CoSerial m BL.ByteString where
+    coseries rs =
+        alts0 rs >>- \y ->
+        alts2 rs >>- \f ->
+            return $ \bs -> case BL.uncons bs of
+                Nothing -> y
+                Just (b,bs') -> f (BL.singleton b) bs'
 
 instance Monad m => Serial m T.Text where
     series = Series.Text.replicateA
+instance Monad m => CoSerial m T.Text where
+    coseries rs =
+        alts0 rs >>- \y ->
+        alts2 rs >>- \f ->
+            return $ \bs -> case T.uncons bs of
+                Nothing -> y
+                Just (b,bs') -> f (T.singleton b) bs'
 
 instance Monad m => Serial m TL.Text where
     series = Series.Text.Lazy.replicateA
+instance Monad m => CoSerial m TL.Text where
+    coseries rs =
+        alts0 rs >>- \y ->
+        alts2 rs >>- \f ->
+            return $ \bs -> case TL.uncons bs of
+                Nothing -> y
+                Just (b,bs') -> f (TL.singleton b) bs'
 
-instance (Serial m k, Serial m v) => Serial m (Map.Map k v) where
+instance (Serial m k, Serial m v) => Serial m (Map k v) where
     series = Map.singleton <$> series <~> series
+instance (Ord k, CoSerial m k, CoSerial m v) => CoSerial m (Map k v) where
+    coseries rs =
+        alts0 rs >>- \y ->
+        alts2 rs >>- \f ->
+            return $ \m -> case pop m of
+                Nothing -> y
+                Just ((k,v), m') -> f (Map.singleton k v) m'
+      where
+        pop m = case Map.toList m of
+                     [] -> Nothing
+                     (kv:its) -> Just (kv, Map.fromList its)
diff --git a/smallcheck-series.cabal b/smallcheck-series.cabal
--- a/smallcheck-series.cabal
+++ b/smallcheck-series.cabal
@@ -1,9 +1,12 @@
 name:                smallcheck-series
-version:             0.3
+version:             0.4
 synopsis:            Extra SmallCheck series and utilities
 description:
-  Orphan @Serial@ instances and utilities to create and manipulate
-  @Series@ for common types.
+  Orphan
+  @<https://hackage.haskell.org/package/smallcheck-1.1.1/docs/Test-SmallCheck-Series.html#t:Serial Serial>@
+  instances and utilities to create and manipulate
+  @<https://hackage.haskell.org/package/smallcheck-1.1.1/docs/Test-SmallCheck-Series.html#t:Series Series>@
+  for common types.
 homepage:            https://github.com/jdnavarro/smallcheck-series
 bug-reports:         https://github.com/jdnavarro/smallcheck-series/issues
 license:             BSD3
diff --git a/tests/doctests.hs b/tests/doctests.hs
--- a/tests/doctests.hs
+++ b/tests/doctests.hs
@@ -1,10 +1,15 @@
+{-# LANGUAGE CPP #-}
 module Main where
 
 import System.FilePath.Glob (glob)
 import Test.DocTest (doctest)
 
 main :: IO ()
+#if !MIN_VERSION_doctest(0,10,1)
 main = doctest . ([ "-idist/build/autogen"
                   , "-optP-include"
                   , "-optPdist/build/autogen/cabal_macros.h"
                   ] ++) =<< glob "Test/**/*.hs"
+#else
+main = doctest =<< glob "Test/**/*.hs"
+#endif