diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # salak
 
-[![Hackage](https://img.shields.io/badge/hackage-v0.2.1-orange.svg)](https://hackage.haskell.org/package/salak)
+[![Hackage](https://img.shields.io/badge/hackage-v0.1.8-orange.svg)](https://hackage.haskell.org/package/salak)
 [![Build Status](https://travis-ci.org/leptonyu/salak.svg?branch=master)](https://travis-ci.org/leptonyu/salak)
 
 
diff --git a/salak.cabal b/salak.cabal
--- a/salak.cabal
+++ b/salak.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.12
 name: salak
-version: 0.1.7
+version: 0.1.8
 license: BSD3
 license-file: LICENSE
 copyright: (c) 2018 Daniel YU
@@ -27,22 +27,23 @@
         Data.Salak.Aeson
         Data.Salak.Yaml
         Data.Salak.Operation
+        Data.Salak.Dynamic
     default-language: Haskell2010
-    ghc-options: -Wall -Wcompat -Wincomplete-record-updates
-                 -Wincomplete-uni-patterns -Wredundant-constraints -fno-warn-orphans
-                 -fno-warn-missing-signatures
+    ghc-options: -Wall -fno-warn-orphans -fno-warn-missing-signatures
     build-depends:
-        aeson >=1.4.2.0 && <1.5,
-        base >=4.11 && <5,
-        directory >=1.3.3.0 && <1.4,
-        filepath >=1.4.2.1 && <1.5,
-        mtl >=2.2.2 && <2.3,
-        scientific >=0.3.6.2 && <0.4,
-        text >=1.2.3.1 && <1.3,
-        transformers >=0.5.5.0 && <0.6,
-        unordered-containers >=0.2.9.0 && <0.3,
-        vector >=0.12.0.2 && <0.13,
-        yaml >=0.11.0.0 && <0.12
+        aeson <1.5,
+        base >=4.7 && <5,
+        directory <1.4,
+        filepath <1.5,
+        menshen <0.1,
+        mtl <2.3,
+        scientific <0.4,
+        stm <2.6,
+        text <1.3,
+        transformers <0.6,
+        unordered-containers <0.3,
+        vector <0.13,
+        yaml <0.12
 
 test-suite spec
     type: exitcode-stdio-1.0
@@ -52,28 +53,27 @@
         Data.Salak
         Data.Salak.Aeson
         Data.Salak.CommandLine
+        Data.Salak.Dynamic
         Data.Salak.Environment
         Data.Salak.Operation
         Data.Salak.Types
         Data.Salak.Yaml
         Paths_salak
     default-language: Haskell2010
-    ghc-options: -Wall -Wcompat -Wincomplete-record-updates
-                 -Wincomplete-uni-patterns -Wredundant-constraints -fno-warn-orphans
-                 -fno-warn-missing-signatures
+    ghc-options: -Wall -fno-warn-orphans -fno-warn-missing-signatures
     build-depends:
-        QuickCheck >=2.12.6.1 && <2.13,
-        aeson >=1.4.2.0 && <1.5,
-        aeson-pretty >=0.8.7 && <0.9,
-        base >=4.11 && <5,
-        bytestring >=0.10.8.2 && <0.11,
-        directory >=1.3.3.0 && <1.4,
-        filepath >=1.4.2.1 && <1.5,
+        QuickCheck <2.13,
+        aeson <1.5,
+        base >=4.7 && <5,
+        directory <1.4,
+        filepath <1.5,
         hspec ==2.*,
-        mtl >=2.2.2 && <2.3,
-        scientific >=0.3.6.2 && <0.4,
-        text >=1.2.3.1 && <1.3,
-        transformers >=0.5.5.0 && <0.6,
-        unordered-containers >=0.2.9.0 && <0.3,
-        vector >=0.12.0.2 && <0.13,
-        yaml >=0.11.0.0 && <0.12
+        menshen <0.1,
+        mtl <2.3,
+        scientific <0.4,
+        stm <2.6,
+        text <1.3,
+        transformers <0.6,
+        unordered-containers <0.3,
+        vector <0.13,
+        yaml <0.12
diff --git a/src/Data/Salak.hs b/src/Data/Salak.hs
--- a/src/Data/Salak.hs
+++ b/src/Data/Salak.hs
@@ -36,7 +36,6 @@
   -- * Types
   , Property(..)
   , Properties(..)
-  , Key
   , FromProperties(..)
   , Return
   -- * Properties Loader Helper
@@ -46,12 +45,15 @@
   , FileName
   -- * Operations
   , module Data.Salak.Operation
+  -- * Dynamic Load
+  , module Data.Salak.Dynamic
   ) where
 
 import           Control.Monad.Trans.Class (lift)
 import           Data.Maybe
 import           Data.Salak.Aeson
 import           Data.Salak.CommandLine
+import           Data.Salak.Dynamic
 import           Data.Salak.Environment
 import           Data.Salak.Operation
 import           Data.Salak.Types
diff --git a/src/Data/Salak/Aeson.hs b/src/Data/Salak/Aeson.hs
--- a/src/Data/Salak/Aeson.hs
+++ b/src/Data/Salak/Aeson.hs
@@ -7,7 +7,9 @@
 import           Control.Monad.IO.Class
 import           Control.Monad.State
 import           Data.Aeson
+import           Data.Aeson.Types
 import qualified Data.HashMap.Strict    as M
+import           Data.Menshen
 import           Data.Salak.Types
 import           Data.Vector            (toList)
 
@@ -24,6 +26,9 @@
 
 jsonToProperties :: Value -> Properties
 jsonToProperties = (`makePropertiesFromJson` empty)
+
+instance HasValid Parser where
+  invalid = fail . toI18n
 
 fromArray v = foldl g3 ([],[]) $ go . jsonToProperties <$> toList v
   where
diff --git a/src/Data/Salak/Dynamic.hs b/src/Data/Salak/Dynamic.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Salak/Dynamic.hs
@@ -0,0 +1,56 @@
+module Data.Salak.Dynamic(
+    LoaderT
+  , load
+  , runLoader
+  , askSetProperties
+  ) where
+
+import           Control.Concurrent.STM.TVar
+import           Control.Monad.IO.Class      (MonadIO, liftIO)
+import           Control.Monad.State
+import           Control.Monad.STM
+import qualified Data.HashMap.Strict         as M
+import           Data.Salak.Operation
+import           Data.Salak.Types
+import           Data.Text                   (Text)
+
+type Loader = (IO Properties, Properties -> IO ())
+
+type LoaderT = StateT Loader
+
+dynamicLoader :: Properties -> IO Loader
+dynamicLoader mp = do
+  m <- newTVarIO mp
+  return (readTVarIO m,\np -> atomically $ modifyTVar' m (go np))
+  where
+    go (Properties [] m1) (Properties p m2) = Properties p (gm m1 m2)
+    go (Properties p  m1) (Properties _ m2) = Properties p (gm m1 m2)
+    gm [] m    = m
+    gm [m] [n] = [M.unionWithKey (\_ -> go) m n]
+    gm m _     = m
+
+-- | Load default properties
+load :: (FromProperties a, MonadIO m, Show a) => Text -> LoaderT m (IO a)
+load key = do
+  (iop, ios) <- get
+  p <- liftIO iop
+  v <- liftIO $ newTVarIO $ p .>> key
+  let go np = do
+        ios np
+        p' <- iop
+        let a = p' .>> key
+        atomically $ writeTVar v a
+  put (iop, go)
+  return (readTVarIO v)
+
+-- | Run loader
+runLoader :: MonadIO m => Properties -> LoaderT m a -> m a
+runLoader p a = do
+  l <- liftIO $ dynamicLoader p
+  fst <$> runStateT a l
+
+-- | Ask properties setter.
+askSetProperties :: MonadIO m => LoaderT m (Properties -> m ())
+askSetProperties = do
+  (_, ios) <- get
+  return $ liftIO . ios
diff --git a/src/Data/Salak/Operation.hs b/src/Data/Salak/Operation.hs
--- a/src/Data/Salak/Operation.hs
+++ b/src/Data/Salak/Operation.hs
@@ -35,5 +35,5 @@
 (.>>) :: FromProperties a => Properties -> Text -> a
 (.>>) p key = case p .?> key of
   Right v           -> v
-  Left (EmptyKey k) -> error $ "property " <> unpack k <> " not set"
+  Left (EmptyKey k) -> error $ "property " ++ unpack k ++ " not set"
   Left (Fail e)     -> error e
diff --git a/src/Data/Salak/Types.hs b/src/Data/Salak/Types.hs
--- a/src/Data/Salak/Types.hs
+++ b/src/Data/Salak/Types.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP                  #-}
 {-# LANGUAGE FlexibleInstances    #-}
 {-# LANGUAGE OverloadedStrings    #-}
 {-# LANGUAGE ScopedTypeVariables  #-}
@@ -5,12 +6,13 @@
 
 module Data.Salak.Types where
 
-import           Control.Monad       ((>=>))
+import           Control.Monad       ()
 import           Control.Monad.State
 import           Data.Char
 import qualified Data.HashMap.Strict as M
 import           Data.Int
 import           Data.Maybe
+import           Data.Menshen
 import           Data.Scientific
 import           Data.String
 import           Data.Text           (Text)
@@ -18,7 +20,9 @@
 import           Data.Word
 import           System.Directory
 import           Text.Read           (readMaybe)
-
+#if __GLASGOW_HASKELL__ <= 802
+import           Data.Monoid         ((<>))
+#endif
 -- | Property key
 type Key = Text
 
@@ -120,6 +124,9 @@
 -- | Return of `FromProperties`
 type Return = Either ErrResult
 data ErrResult = EmptyKey Text | Fail String deriving Show
+
+instance HasValid Return where
+  invalid = Left . Fail . toI18n
 
 -- | Convert `Properties` to Haskell value.
 class FromProperties a where
diff --git a/src/Data/Salak/Yaml.hs b/src/Data/Salak/Yaml.hs
--- a/src/Data/Salak/Yaml.hs
+++ b/src/Data/Salak/Yaml.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 module Data.Salak.Yaml where
 
 import           Control.Monad.IO.Class
@@ -9,7 +10,16 @@
 -- | Load `Properties` from `Yaml` file.
 makePropertiesFromYaml :: FilePath -> Properties -> IO Properties
 makePropertiesFromYaml file p = do
+
+#if __GLASGOW_HASKELL__ <= 710
+  x <- decodeFile file
+  v <- case x of
+    Just a -> return a
+    _      -> error $ "load " ++ file ++ " failed"
+#else
   v <- decodeFileThrow file
+#endif
+
   return $ makePropertiesFromJson v p
 
 -- | Load Properties from Yaml
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -18,10 +18,11 @@
 
 spec :: Spec
 spec = do
-  describe "Data.Salak.Types" specProperty
-  describe "Data.Salak"       specProperties
+  describe "Data.Salak.Types"   specProperty
+  describe "Data.Salak"         specProperties
+  describe "Data.Salak.Dynamic" specDynamic
 
-shouldFail :: (HasCallStack, Show a, Eq a) => a -> a -> Expectation
+shouldFail :: (Show a, Eq a) => a -> a -> Expectation
 shouldFail f a = (f `shouldBe` a) `shouldThrow` anyErrorCall
 
 data Config = Config
@@ -122,6 +123,19 @@
       (p .>> "array"        :: Maybe [String]) `shouldBe`   Just ["a","b"]
       (p .>> "array"        :: Maybe [Int])    `shouldFail` Nothing
       (p .>> "array"        :: Maybe String)   `shouldFail` Nothing
+
+specDynamic = do
+  context "Dynamic" $ do
+    it "dynamic load" $ do
+      p  <- defaultPropertiesWithFile "salak.yml"
+      (c,s) <- runLoader p $ (,) <$> load "config" <*> askSetProperties
+      c1 <- c
+      s $ insert ["config","name"] "world" empty
+      c2 <- c
+      name c1 `shouldBe` "hello"
+      name c2 `shouldBe` "world"
+      dir c1  `shouldBe` dir c2
+      ext c1  `shouldBe` ext c2
 
 
 
diff --git a/test/salak.yml b/test/salak.yml
--- a/test/salak.yml
+++ b/test/salak.yml
@@ -1,3 +1,9 @@
 array:
   - a
   - b
+hello:
+  world
+
+config:
+  name: hello
+  dir: /root