diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,8 @@
+4.3.1
+---
+* Added `Data.Bits.bytewise`
+* Support `aeson` 0.8.0.0
+
 4.3
 ---
 * Switched the "direction" of the `Iso` argument to `au` to match the order generated by `makePrisms` and `makeLenses`.
diff --git a/lens.cabal b/lens.cabal
--- a/lens.cabal
+++ b/lens.cabal
@@ -1,6 +1,6 @@
 name:          lens
 category:      Data, Lenses, Generics
-version:       4.3
+version:       4.3.1
 license:       BSD3
 cabal-version: >= 1.8
 license-file:  LICENSE
@@ -181,7 +181,7 @@
 
 library
   build-depends:
-    aeson                     >= 0.7.0.5  && < 0.8,
+    aeson                     >= 0.7.0.5  && < 0.9,
     attoparsec                >= 0.10     && < 0.13,
     array                     >= 0.3.0.2  && < 0.6,
     base                      >= 4.3      && < 5,
diff --git a/src/Control/Lens/Iso.hs b/src/Control/Lens/Iso.hs
--- a/src/Control/Lens/Iso.hs
+++ b/src/Control/Lens/Iso.hs
@@ -497,8 +497,8 @@
 -- | Lift two 'Iso's into both arguments of a 'Bifunctor'.
 --
 -- @
--- bimapping :: 'Profunctor' p => 'Iso' s t a b -> 'Iso' s' t' a' b' -> 'Iso' (p s s') (p t t') (p a a') (p b b')
--- bimapping :: 'Profunctor' p => 'Iso'' s a -> 'Iso'' s' a' -> 'Iso'' (p s s') (p a a')
+-- bimapping :: 'Bifunctor' p => 'Iso' s t a b -> 'Iso' s' t' a' b' -> 'Iso' (p s s') (p t t') (p a a') (p b b')
+-- bimapping :: 'Bifunctor' p => 'Iso'' s a -> 'Iso'' s' a' -> 'Iso'' (p s s') (p a a')
 -- @
 bimapping :: (Bifunctor f, Bifunctor g) => AnIso s t a b -> AnIso s' t' a' b' -> Iso (f s s') (g t t') (f a a') (g b b')
 bimapping f g = withIso f $ \ sa bt -> withIso g $ \s'a' b't' ->
diff --git a/src/Data/Bits/Lens.hs b/src/Data/Bits/Lens.hs
--- a/src/Data/Bits/Lens.hs
+++ b/src/Data/Bits/Lens.hs
@@ -16,6 +16,7 @@
   , bitAt
   , bits
   , byteAt
+  , bytewise
   ) where
 
 import Control.Lens
@@ -223,3 +224,23 @@
   step (n,True) r = setBit r n
   step _        r = r
 {-# INLINE bits #-}
+
+-- | Traverse over all the bytes in an integral type, from the low end.
+--
+-- The byte position is available as the index.
+--
+-- >>> toListOf bytewise (1312301580 :: Word32)
+-- [12,34,56,78]
+--
+-- If you supply this an 'Integer', the result will be an infinite 'Traversal',
+-- which can be productively consumed, but not reassembled.
+--
+-- Why is this function called @bytes@ to match 'bits'? Alas, there is already
+-- a function by that name in "Data.ByteString.Lens".
+bytewise :: (Integral b, Bits b) => IndexedTraversal' Int b Word8
+bytewise f b = Prelude.foldr step 0 <$> traverse g bs where
+  g n = (,) n <$> indexed f n (fromIntegral $ b `shiftR` (n*8))
+  bs = Prelude.takeWhile hasByte [0..]
+  hasByte n = complementBit b (n*8) /= b
+  step (n,x) r = r .|. (fromIntegral x `shiftL` (n*8))
+{-# INLINE bytewise #-}