diff --git a/network-bitcoin.cabal b/network-bitcoin.cabal
--- a/network-bitcoin.cabal
+++ b/network-bitcoin.cabal
@@ -7,7 +7,7 @@
 -- The package version. See the Haskell package versioning policy
 -- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
 -- standards guiding when and how versions should be incremented.
-Version:             0.1.2
+Version:             0.1.3
 
 -- A short (one-line) description of the package.
 Synopsis:            Interface with Bitcoin RPC
@@ -28,9 +28,13 @@
     .
     To learn more about Bitcoin, see <http://www.bitcoin.org>.
     .
-    Changes in v0.1.2
+    Changes in v0.1.3
     .
-    - support building on GHC 7.2
+    - Be more lenient when accepting addresses
+    .
+    - Support testnet addresses
+    .
+    - Add FlexibleInstances for GHC 7.2
 
 -- The license under which the package is released.
 License:             BSD3
diff --git a/src/Network/Bitcoin.hs b/src/Network/Bitcoin.hs
--- a/src/Network/Bitcoin.hs
+++ b/src/Network/Bitcoin.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
 -- | Communicate with a Bitcoin daemon over JSON RPC
 module Network.Bitcoin
     (
diff --git a/src/Network/Bitcoin/Address.hs b/src/Network/Bitcoin/Address.hs
--- a/src/Network/Bitcoin/Address.hs
+++ b/src/Network/Bitcoin/Address.hs
@@ -26,5 +26,7 @@
         then Just $ Address s
         else Nothing
   where -- TODO validate address checksum (write base58 module first)
-    isOK ('1':_) = (length s == 34)
+    isOK ('1':_) = (length s >= 25) && (length s <= 34)
+    isOK ('m':_) = (length s >= 26) && (length s <= 34)
+    isOK ('n':_) = (length s >= 26) && (length s <= 34)
     isOK _       = False