diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,15 @@
+Version 4.0.1
+-----
+
+* Fixed build issues on GHC 7.10.1.
+
+Version 4.0
+-----
+
+* Added resource preemption.
+
+* Fixed misprint in the activityProcessor function.
+
 Version 3.1
 -----
 
diff --git a/Simulation/Aivika/PriorityQueue.hs b/Simulation/Aivika/PriorityQueue.hs
--- a/Simulation/Aivika/PriorityQueue.hs
+++ b/Simulation/Aivika/PriorityQueue.hs
@@ -1,4 +1,6 @@
 
+{-# LANGUAGE FlexibleContexts #-}
+
 -- |
 -- Module     : Simulation.Aivika.PriorityQueue
 -- Copyright  : Copyright (c) 2009-2015, David Sorokin <david.sorokin@gmail.com>
diff --git a/Simulation/Aivika/Unboxed.hs b/Simulation/Aivika/Unboxed.hs
--- a/Simulation/Aivika/Unboxed.hs
+++ b/Simulation/Aivika/Unboxed.hs
@@ -17,8 +17,8 @@
 
 import Data.Array
 import Data.Array.IO.Safe
-import Data.Int	 
-import Data.Word	 
+import Data.Int
+import Data.Word 
 
 -- | The type which values can be contained in an unboxed array.
 class MArray IOUArray e IO => Unboxed e where
@@ -27,18 +27,18 @@
   newUnboxedArray_ :: Ix i => (i, i) -> IO (IOUArray i e)
   newUnboxedArray_ = newArray_
 
-instance Unboxed Bool	 
-instance Unboxed Char	 
-instance Unboxed Double	 
-instance Unboxed Float	 
-instance Unboxed Int	 
-instance Unboxed Int8	 
-instance Unboxed Int16	 
-instance Unboxed Int32	 
-instance Unboxed Word	 
-instance Unboxed Word8	 
-instance Unboxed Word16	 
-instance Unboxed Word32	 
+instance Unboxed Bool
+instance Unboxed Char
+instance Unboxed Double
+instance Unboxed Float
+instance Unboxed Int
+instance Unboxed Int8
+instance Unboxed Int16
+instance Unboxed Int32
+instance Unboxed Word
+instance Unboxed Word8
+instance Unboxed Word16
+instance Unboxed Word32
 
 #ifndef __HASTE__
 
diff --git a/Simulation/Aivika/Vector.hs b/Simulation/Aivika/Vector.hs
--- a/Simulation/Aivika/Vector.hs
+++ b/Simulation/Aivika/Vector.hs
@@ -1,4 +1,6 @@
 
+{-# LANGUAGE FlexibleContexts #-}
+
 -- |
 -- Module     : Simulation.Aivika.Vector
 -- Copyright  : Copyright (c) 2009-2015, David Sorokin <david.sorokin@gmail.com>
diff --git a/Simulation/Aivika/Vector/Unboxed.hs b/Simulation/Aivika/Vector/Unboxed.hs
--- a/Simulation/Aivika/Vector/Unboxed.hs
+++ b/Simulation/Aivika/Vector/Unboxed.hs
@@ -1,4 +1,6 @@
 
+{-# LANGUAGE FlexibleContexts #-}
+
 -- |
 -- Module     : Simulation.Aivika.Vector.Unboxed
 -- Copyright  : Copyright (c) 2009-2015, David Sorokin <david.sorokin@gmail.com>
diff --git a/aivika.cabal b/aivika.cabal
--- a/aivika.cabal
+++ b/aivika.cabal
@@ -1,5 +1,5 @@
 name:            aivika
-version:         4.0
+version:         4.0.1
 synopsis:        A multi-paradigm simulation library
 description:
     Aivika is a multi-paradigm simulation library with a strong emphasis
@@ -110,11 +110,6 @@
                      examples/TimeOutWait.hs
                      CHANGELOG.md
 
-flag haste-inst
-    
-    description: The package is built using haste-inst
-    default:     False
-
 library
 
     exposed-modules: Simulation.Aivika
@@ -187,10 +182,8 @@
                      mtl >= 2.1.1,
                      array >= 0.3.0.0,
                      containers >= 0.4.0.0,
-                     random >= 1.0.0.3
-
-    if !flag(haste-inst)
-       build-depends:   vector >= 0.10.0.1
+                     random >= 1.0.0.3,
+                     vector >= 0.10.0.1
 
     other-extensions:   FlexibleContexts,
                         FlexibleInstances,