5.4.2

• Make deriveBitraversable use liftA2 in derived implementations of bitraverse when possible, now that liftA2 is a class method of Applicative (as of GHC 8.2)
• Backport slightly more efficient implementations of bimapDefault and bifoldMapDefault

5.4.1

• Add explicit Safe, Trustworthy, and Unsafe annotations. In particular, annotate the Data.Bifoldable module as Trustworthy (previously, it was inferred to be Unsafe).

5.4

• Only export Data.Bifoldable and Data.Bitraversable when building on GHC < 8.1, otherwise they come from base
• Allow TH derivation of Bifunctor and Bifoldable instances for datatypes containing unboxed tuple types

5.3

• Added bifoldr1, bifoldl1, bimsum, biasum, binull, bilength, bielem, bimaximum, biminimum, bisum, biproduct, biand, bior, bimaximumBy, biminimumBy, binotElem, and bifind to Data.Bifoldable
• Added Bifunctor, Bifoldable, and Bitraversable instances for GHC.Generics.K1
• TH code no longer generates superfluous mempty or pure subexpressions in derived Bifoldable or Bitraversable instances, respectively

5.2.1

• Added Bifoldable and Bitraversable instances for Constant from transformers
• Data.Bifunctor.TH now compiles warning-free on GHC 8.0

5.2

• Added several Arrow-like instances for Tannen so we can use it as the Cayley construction if needed.
• Added Data.Bifunctor.Sum
• Added BifunctorFunctor, BifunctorMonad and BifunctorComonad.
• Backported Bifunctor Constant instance from transformers

5.1

• Added Data.Bifunctor.Fix
• Added Data.Bifunctor.TH, which permits TemplateHaskell-based deriving of Bifunctor, Bifoldable and Bitraversable instances.
• Simplified Bitraversable.

5 - Inverted the dependency on semigroupoids. We can support a much wider array of base versions than it can. Added flags

4.2.1

• Support Arg from semigroups 0.16.2
• Fixed a typo.

4.2

• Bumped dependency on tagged, which is required to build cleanly on GHC 7.9+
• Only export Data.Bifunctor when building on GHC < 7.9, otherwise it comes from base.

4.1.1.1

• Added documentation for 'Bifoldable' and 'Bitraversable'

4.1.1

• Added Data.Bifunctor.Join
• Fixed improper lower bounds on base

4.1.0.1

• Updated to BSD 2-clause license

4.1

• Added product bifunctors

4.0

• Compatibility with semigroupoids 4.0

3.2

• Added missing product instances for Biapplicative and Biapply.

3.1

• Added Data.Biapplicative.
• Added the Clown and Joker bifunctors from Conor McBride's "Clowns to the left of me, Jokers to the right."
• Added instances for Const, higher tuples
• Added Tagged instances.

3.0.4

• Added Data.Bifunctor.Flip and Data.Bifunctor.Wrapped.

3.0.3

• Removed upper bounds from my other package dependencies