diff --git a/snmp.cabal b/snmp.cabal
--- a/snmp.cabal
+++ b/snmp.cabal
@@ -1,5 +1,5 @@
 name:                snmp
-version:             0.1.0.0
+version:             0.1.0.1
 synopsis:            API for write snmp client.
 description:         API for write snmp client.        
 license:             BSD3
@@ -20,7 +20,7 @@
   exposed-modules: Network.Protocol.Snmp, Network.Snmp.Client, Network.Snmp.Example
   other-modules: Network.Snmp.Client.Internal, Network.Snmp.Client.Types, Network.Snmp.Client.Version2, Network.Snmp.Client.Version3     
   -- other-extensions:    
-  build-depends:       base >=4.7 && <4.8, 
+  build-depends:       base >=4.6 && <4.8, 
                        asn1-encoding, 
                        asn1-types, 
                        asn1-parse, 
diff --git a/src/Network/Protocol/Snmp.hs b/src/Network/Protocol/Snmp.hs
--- a/src/Network/Protocol/Snmp.hs
+++ b/src/Network/Protocol/Snmp.hs
@@ -4,6 +4,7 @@
 {-# LANGUAGE StandaloneDeriving #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE GADTs #-}
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleInstances #-}
 module Network.Protocol.Snmp (
 -- * snmp types
@@ -113,7 +114,11 @@
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Lazy as BL
 import Data.Word (Word8, Word32, Word64)
+#if MIN_VERSION_base(4,7,0)
 import Data.Bits (testBit, complement, shiftL, (.|.), (.&.), setBit, shiftR, zeroBits, xor, clearBit)
+#else
+import Data.Bits (testBit, complement, shiftL, (.|.), (.&.), setBit, shiftR, xor, clearBit, Bits(..))
+#endif
 import Data.ASN1.Types (ASN1Object(..), ASN1(..), OID, ASN1ConstructionType(..), ASN1Class(..))
 import Data.ASN1.Parse (getNext, getObject, runParseASN1, runParseASN1State, ParseASN1, getNextContainer, onNextContainer, getMany)
 import Data.ASN1.BinaryEncoding (DER(..))
@@ -171,6 +176,15 @@
 
 fI :: (Num b, Integral a) => a -> b
 fI = fromIntegral
+
+#if MIN_VERSION_base(4,7,0)
+#else
+zeroBits :: (Num a, Bits a) =>  a
+zeroBits = clearBit (bit 0) 0
+  where
+  bit :: (Bits a, Num a) => Int -> a
+  bit i = 1 `shiftL` i
+#endif
 
 -- | Phantom type for version 2 (Header V2, PDU V2)
 data V2