diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog for elm2nix
 
+## 0.3.0 (2022-09-06)
+
+- Prevent duplicates between src and test dependencies (@gpampara)
+- #48 Aeson 2 support (@gpampara)
+
 ## 0.2.1 (2020-11-22)
 
 - #40 Fix compatibility with newer versions of uglify.js (@turboMaCk)
diff --git a/elm2nix.cabal b/elm2nix.cabal
--- a/elm2nix.cabal
+++ b/elm2nix.cabal
@@ -3,14 +3,14 @@
 -- see: https://github.com/sol/hpack
 
 name:           elm2nix
-version: 0.2.1
+version: 0.3.0
 synopsis:       Turn your Elm project into buildable Nix project
 description:    Please see the README on Github at <https://github.com/domenkozar/elm2nix#readme>
 homepage:       https://github.com/domenkozar/elm2nix#readme
 bug-reports:    https://github.com/domenkozar/elm2nix/issues
-author:         Domen Kožar
+author:         Domen Kozar
 maintainer:     domen@dev.si
-copyright:      2017-2019 Domen Kožar
+copyright:      2017-2022 Domen Kozar
 license:        BSD3
 license-file:   LICENSE
 build-type:     Simple
diff --git a/elm2nix/Main.hs b/elm2nix/Main.hs
--- a/elm2nix/Main.hs
+++ b/elm2nix/Main.hs
@@ -47,6 +47,7 @@
 
       $ elm2nix init > default.nix
       $ elm2nix convert > elm-srcs.nix
+      $ elm2nix snapshot
       $ nix-build
 
       Note: You have to run elm2nix from top-level directory of an Elm project.
@@ -56,5 +57,5 @@
     opts = subparser
       ( command "init" (infoH (pure Init) (progDesc "Generate default.nix (printed to stdout)"))
      <> command "convert" (infoH (pure Convert) (progDesc "Generate Nix expressions for elm.json using nix-prefetch-url"))
-     <> command "snapshot" (infoH (pure Snapshot) (progDesc "Generate versions.dat"))
+     <> command "snapshot" (infoH (pure Snapshot) (progDesc "Generate registry.dat"))
       )
diff --git a/src/Elm2Nix.hs b/src/Elm2Nix.hs
--- a/src/Elm2Nix.hs
+++ b/src/Elm2Nix.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE QuasiQuotes #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE CPP #-}
 
 module Elm2Nix
     ( convert
@@ -13,14 +14,20 @@
 import Control.Monad.Except (liftIO, MonadIO)
 import Control.Monad.Trans.Except (ExceptT, runExceptT, throwE)
 import Data.Aeson (Value(..))
-import Data.List (intercalate)
+import Data.List (intercalate, nub)
 import Data.HashMap.Strict (HashMap)
 import Data.String.Here
 import Data.Text (Text)
 import System.Exit (exitFailure)
 import System.IO (hPutStrLn, stderr)
 
+#if MIN_VERSION_aeson(2,0,0)
+import qualified Data.Aeson.Key as AK
+import qualified Data.Aeson.KeyMap as HM
+#else
 import qualified Data.HashMap.Strict as HM
+#endif
+
 import qualified Data.ByteString.Lazy as LBS
 import qualified Data.Aeson as Json
 import qualified Data.Text as Text
@@ -59,8 +66,13 @@
         v -> Left (UnexpectedValue v)
     v -> Left (UnexpectedValue v)
   where
+#if MIN_VERSION_aeson(2,0,0)
+    parseDep :: Json.Key -> Value -> Either Elm2NixError Dep
+    parseDep name (String ver) = Right (Text.unpack (AK.toText name), Text.unpack ver)
+#else
     parseDep :: Text -> Value -> Either Elm2NixError Dep
     parseDep name (String ver) = Right (Text.unpack name, Text.unpack ver)
+#endif
     parseDep _ v               = Left (UnexpectedValue v)
 
     parseDeps :: Value -> Either Elm2NixError [Dep]
@@ -71,9 +83,15 @@
     maybeToRight _ (Just x) = Right x
     maybeToRight y Nothing  = Left y
 
+#if MIN_VERSION_aeson(2,0,0)
+    tryLookup :: HM.KeyMap Value -> Text -> Either Elm2NixError Value
+    tryLookup hm key =
+      maybeToRight (KeyNotFound key) (HM.lookup (AK.fromText key) hm)
+#else
     tryLookup :: HashMap Text Value -> Text -> Either Elm2NixError Value
     tryLookup hm key =
       maybeToRight (KeyNotFound key) (HM.lookup key hm)
+#endif
 
 -- CMDs
 
@@ -87,7 +105,7 @@
   testDeps <- either throwErr return (parseElmJsonDeps "test-dependencies" elmJson)
   liftIO (hPutStrLn stderr "Prefetching tarballs and computing sha256 hashes ...")
 
-  sources <- liftIO (mapConcurrently (uncurry prefetch) (deps ++ testDeps))
+  sources <- liftIO (mapConcurrently (uncurry prefetch) (nub $ deps ++ testDeps))
   liftIO (putStrLn (generateNixSources sources))
 
 initialize :: IO ()