diff --git a/Distribution/Cab/GenPaths.hs b/Distribution/Cab/GenPaths.hs
--- a/Distribution/Cab/GenPaths.hs
+++ b/Distribution/Cab/GenPaths.hs
@@ -50,4 +50,5 @@
         []      -> throwIO $ userError "Cabal file does not exist"
         cfile:_ -> return cfile
   where
+    isCabal :: String -> Bool
     isCabal nm = ".cabal" `isSuffixOf` nm && length nm > 6
diff --git a/Distribution/Cab/PkgDB.hs b/Distribution/Cab/PkgDB.hs
--- a/Distribution/Cab/PkgDB.hs
+++ b/Distribution/Cab/PkgDB.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 module Distribution.Cab.PkgDB (
   -- * Types
     PkgDB
@@ -30,13 +31,21 @@
 import Distribution.Simple.Compiler (PackageDB(..))
 import Distribution.Simple.GHC (configure, getInstalledPackages, getPackageDBContents)
 import Distribution.Simple.PackageIndex
-    (lookupPackageName, lookupSourcePackageId
-    , allPackages, fromList, reverseDependencyClosure
-    , topologicalOrder, PackageIndex)
+    (lookupPackageName, lookupSourcePackageId, allPackages
+    , fromList, reverseDependencyClosure, topologicalOrder)
+#if MIN_VERSION_Cabal(1,22,0)
+import Distribution.Simple.PackageIndex (InstalledPackageIndex)
+#else
+import Distribution.Simple.PackageIndex (PackageIndex)
+#endif
 import Distribution.Simple.Program.Db (defaultProgramDb)
 import Distribution.Verbosity (normal)
 
+#if MIN_VERSION_Cabal(1,22,0)
+type PkgDB = InstalledPackageIndex
+#else
 type PkgDB = PackageIndex
+#endif
 type PkgInfo = InstalledPackageInfo
 
 ----------------------------------------------------------------
@@ -63,12 +72,12 @@
 toUserSpec Nothing     = UserPackageDB
 toUserSpec (Just path) = SpecificPackageDB path
 
-getDBs :: [PackageDB] -> IO PackageIndex
+getDBs :: [PackageDB] -> IO PkgDB
 getDBs specs = do
     (_,_,pro) <- configure normal Nothing Nothing defaultProgramDb
     getInstalledPackages normal specs pro
 
-getDB :: PackageDB -> IO PackageIndex
+getDB :: PackageDB -> IO PkgDB
 getDB spec = do
     (_,_,pro) <- configure normal Nothing Nothing defaultProgramDb
     getPackageDBContents normal spec pro
diff --git a/cab.cabal b/cab.cabal
--- a/cab.cabal
+++ b/cab.cabal
@@ -1,5 +1,5 @@
 Name:                   cab
-Version:                0.2.14
+Version:                0.2.15
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3
@@ -21,7 +21,7 @@
   Default-Language:     Haskell2010
   GHC-Options:          -Wall
   Build-Depends:        base >= 4.0 && < 5
-                      , Cabal >= 1.18 && < 1.21
+                      , Cabal >= 1.18 && < 1.23
                       , attoparsec >= 0.10
                       , bytestring
                       , conduit >= 1.1
@@ -56,7 +56,7 @@
                       , containers
                       , directory
                       , filepath
-                      , process >= 1.2.0.0
+                      , process
   Other-Modules:	Commands
                         Doc
                         Help
diff --git a/src/Run.hs b/src/Run.hs
--- a/src/Run.hs
+++ b/src/Run.hs
@@ -1,8 +1,14 @@
+{-# LANGUAGE CPP #-}
 module Run (run, toSwitch) where
 
 import Data.List (intercalate)
 import Distribution.Cab
+#if MIN_VERSION_process(1,2,0)
 import System.Process (callCommand)
+#else
+import Control.Monad (void)
+import System.Cmd (system)
+#endif
 
 import Types
 
@@ -55,8 +61,14 @@
     options = optionsToString opts sws
 
 callProcess :: String -> [String] -> [Arg] -> [String] -> IO ()
-callProcess pro args0 args1 options = callCommand script
+callProcess pro args0 args1 options = systemCommand script
   where
+#if MIN_VERSION_process(1,2,0)
+    systemCommand = callCommand
+#else
+    systemCommand = void . system
+#endif
+
     script = intercalate " " $ pro : args0 ++ cat args1 ++ options
     cat [pkg,ver] = [pkg ++ "-" ++ ver]
     cat x         = x