diff --git a/Changelog.md b/Changelog.md
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,6 +1,12 @@
 # Changelog for `proto-lens-arbitrary`
 
-## Unreleased changes
+## v0.1.2.0
+- Remove support for `ghc-7.10`. (#136)
+- Use a `.cabal` file that's auto-generated from `hpack`. (#138)
+- Track `proto-lens` changes to the `Message` class. (#139, #147)
+- Expose `shrinkMessage` (#159)
+- Improve the `Arbitrary` generator for nested structures (#163)
+
 
 ## v0.1.1.1
 - Bump the dependency on `base` to support `ghc-8.2.1`.
diff --git a/proto-lens-arbitrary.cabal b/proto-lens-arbitrary.cabal
--- a/proto-lens-arbitrary.cabal
+++ b/proto-lens-arbitrary.cabal
@@ -1,28 +1,45 @@
-name:                proto-lens-arbitrary
-version:             0.1.1.1
-synopsis:            Arbitrary instances for proto-lens.
-description:
-  The proto-lens-arbitrary allows generating arbitrary messages for
-  use with QuickCheck.
+-- This file has been generated from package.yaml by hpack version 0.20.0.
+--
+-- see: https://github.com/sol/hpack
+--
+-- hash: 9e84da8b472df0355cae508146fec0dacd00229345ed731b95cc3936649a2364
 
-homepage:            https://github.com/google/proto-lens
-license:             BSD3
-license-file:        LICENSE
-author:              Aden Grue
-maintainer:          agrue+protolens@google.com
-copyright:           Google Inc.
-category:            Data
-build-type:          Simple
-cabal-version:       >=1.8
-extra-source-files:  Changelog.md
+name:           proto-lens-arbitrary
+version:        0.1.2.0
+synopsis:       Arbitrary instances for proto-lens.
+description:    The proto-lens-arbitrary allows generating arbitrary messages for use with QuickCheck.
+category:       Data
+homepage:       https://github.com/google/proto-lens#readme
+bug-reports:    https://github.com/google/proto-lens/issues
+author:         Aden Grue
+maintainer:     agrue+protolens@google.com
+copyright:      Google Inc.
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+cabal-version:  >= 1.10
 
+extra-source-files:
+    Changelog.md
+
+source-repository head
+  type: git
+  location: https://github.com/google/proto-lens
+  subdir: proto-lens-arbitrary
+
 library
-  hs-source-dirs: src
-  exposed-modules:     Data.ProtoLens.Arbitrary
-  build-depends:  proto-lens >= 0.1 && < 0.3
-                , base >= 4.8 && < 4.11
-                , bytestring == 0.10.*
-                , containers == 0.5.*
-                , text == 1.2.*
-                , lens-family == 1.2.*
-                , QuickCheck >= 2.8 && < 2.11
+  hs-source-dirs:
+      src
+  build-depends:
+      QuickCheck >=2.8 && <2.11
+    , base >=4.8 && <4.11
+    , bytestring ==0.10.*
+    , containers ==0.5.*
+    , lens-family ==1.2.*
+    , proto-lens ==0.3.*
+    , text ==1.2.*
+  exposed-modules:
+      Data.ProtoLens.Arbitrary
+  other-modules:
+      Paths_proto_lens_arbitrary
+  default-language: Haskell2010
diff --git a/src/Data/ProtoLens/Arbitrary.hs b/src/Data/ProtoLens/Arbitrary.hs
--- a/src/Data/ProtoLens/Arbitrary.hs
+++ b/src/Data/ProtoLens/Arbitrary.hs
@@ -6,11 +6,13 @@
 
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE GADTs #-}
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE RankNTypes #-}
 -- | An Arbitrary instance for protocol buffer Messages to use with QuickCheck.
 module Data.ProtoLens.Arbitrary
     ( ArbitraryMessage(..)
     , arbitraryMessage
+    , shrinkMessage
     ) where
 
 import Data.ProtoLens.Message
@@ -25,7 +27,7 @@
 import Lens.Family2 (Lens', view, set)
 import Lens.Family2.Unchecked (lens)
 import Test.QuickCheck (Arbitrary(..), Gen, suchThat, frequency, listOf,
-                        shrinkList)
+                        shrinkList, scale)
 
 
 -- | A newtype wrapper that provides an Arbitrary instance for the underlying
@@ -38,9 +40,7 @@
     shrink (ArbitraryMessage a) = ArbitraryMessage <$> shrinkMessage a
 
 arbitraryMessage :: Message a => Gen a
-arbitraryMessage = foldM (flip arbitraryField) def fields
-  where
-    fields = M.elems (fieldsByTag descriptor)
+arbitraryMessage = foldM (flip arbitraryField) def allFields
 
 -- | Imitation of the (Arbitrary a => Arbitrary (Maybe a)) instance from
 -- QuickCheck.
@@ -66,9 +66,12 @@
     fieldGen = arbitraryFieldValue ftd
 
 arbitraryFieldValue :: FieldTypeDescriptor value -> Gen value
-arbitraryFieldValue ftd = case ftd of
-    MessageField -> arbitraryMessage
-    GroupField -> arbitraryMessage
+arbitraryFieldValue = \case
+    MessageField _ -> scale (`div` 2) arbitraryMessage
+    ScalarField f -> arbitraryScalarValue f
+
+arbitraryScalarValue :: ScalarField value -> Gen value
+arbitraryScalarValue = \case
     -- For enum fields, all we know is that the value is an instance of
     -- MessageEnum, meaning we can only use fromEnum, toEnum, or maybeToEnum. So
     -- we must rely on the instance of Arbitrary for Int and filter out only the
@@ -96,9 +99,7 @@
 -- | Shrink each field individually and append all shrinks together into
 -- a single list.
 shrinkMessage :: Message a => a -> [a]
-shrinkMessage msg = concatMap (`shrinkField` msg) fields
-  where
-    fields = M.elems (fieldsByTag descriptor)
+shrinkMessage msg = concatMap (`shrinkField` msg) allFields
 
 shrinkMaybe :: (a -> [a]) -> Maybe a -> [Maybe a]
 shrinkMaybe f (Just v) = Nothing : (Just <$> f v)
@@ -119,9 +120,12 @@
     fieldShrinker = shrinkFieldValue ftd
 
 shrinkFieldValue :: FieldTypeDescriptor value -> value -> [value]
-shrinkFieldValue ftd = case ftd of
-    MessageField -> shrinkMessage
-    GroupField -> map unArbitraryMessage . shrink . ArbitraryMessage
+shrinkFieldValue = \case
+    MessageField _ -> shrinkMessage
+    ScalarField f -> shrinkScalarValue f
+
+shrinkScalarValue :: ScalarField value -> value -> [value]
+shrinkScalarValue = \case
     -- Shrink to the 0-equivalent Enum value if it's both a valid Enum value
     -- and the value isn't already 0.
     EnumField -> case maybeToEnum 0 of