diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+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`
diff --git a/bifunctors.cabal b/bifunctors.cabal
--- a/bifunctors.cabal
+++ b/bifunctors.cabal
@@ -1,6 +1,6 @@
 name:          bifunctors
 category:      Data, Functors
-version:       5.4
+version:       5.4.1
 license:       BSD3
 cabal-version: >= 1.8
 license-file:  LICENSE
diff --git a/old-src/ghc709/Data/Bifunctor.hs b/old-src/ghc709/Data/Bifunctor.hs
--- a/old-src/ghc709/Data/Bifunctor.hs
+++ b/old-src/ghc709/Data/Bifunctor.hs
@@ -2,6 +2,12 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE StandaloneDeriving #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 #ifndef MIN_VERSION_semigroups
 #define MIN_VERSION_semigroups(x,y,z) 0
 #endif
diff --git a/old-src/ghc801/Data/Bifoldable.hs b/old-src/ghc801/Data/Bifoldable.hs
--- a/old-src/ghc801/Data/Bifoldable.hs
+++ b/old-src/ghc801/Data/Bifoldable.hs
@@ -3,6 +3,10 @@
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE StandaloneDeriving #-}
 
+#if __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 #ifndef MIN_VERSION_semigroups
 #define MIN_VERSION_semigroups(x,y,z) 0
 #endif
diff --git a/old-src/ghc801/Data/Bitraversable.hs b/old-src/ghc801/Data/Bitraversable.hs
--- a/old-src/ghc801/Data/Bitraversable.hs
+++ b/old-src/ghc801/Data/Bitraversable.hs
@@ -2,6 +2,12 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE StandaloneDeriving #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 #ifndef MIN_VERSION_semigroups
 #define MIN_VERSION_semigroups(x,y,z) 0
 #endif
diff --git a/src/Data/Biapplicative.hs b/src/Data/Biapplicative.hs
--- a/src/Data/Biapplicative.hs
+++ b/src/Data/Biapplicative.hs
@@ -1,5 +1,9 @@
 {-# LANGUAGE CPP #-}
 
+#if __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Safe #-}
+#endif
+
 #ifndef MIN_VERSION_semigroups
 #define MIN_VERSION_semigroups(x,y,z) 0
 #endif
diff --git a/src/Data/Bifunctor/Biff.hs b/src/Data/Bifunctor/Biff.hs
--- a/src/Data/Bifunctor/Biff.hs
+++ b/src/Data/Bifunctor/Biff.hs
@@ -14,6 +14,12 @@
 {-# LANGUAGE PolyKinds #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 708
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Copyright   :  (C) 2008-2016 Edward Kmett
diff --git a/src/Data/Bifunctor/Clown.hs b/src/Data/Bifunctor/Clown.hs
--- a/src/Data/Bifunctor/Clown.hs
+++ b/src/Data/Bifunctor/Clown.hs
@@ -11,6 +11,12 @@
 {-# LANGUAGE PolyKinds #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 708
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Copyright   :  (C) 2008-2016 Edward Kmett
diff --git a/src/Data/Bifunctor/Fix.hs b/src/Data/Bifunctor/Fix.hs
--- a/src/Data/Bifunctor/Fix.hs
+++ b/src/Data/Bifunctor/Fix.hs
@@ -8,6 +8,12 @@
 {-# LANGUAGE DeriveGeneric #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 #if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
diff --git a/src/Data/Bifunctor/Flip.hs b/src/Data/Bifunctor/Flip.hs
--- a/src/Data/Bifunctor/Flip.hs
+++ b/src/Data/Bifunctor/Flip.hs
@@ -5,6 +5,12 @@
 {-# LANGUAGE DeriveGeneric #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 #if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
diff --git a/src/Data/Bifunctor/Functor.hs b/src/Data/Bifunctor/Functor.hs
--- a/src/Data/Bifunctor/Functor.hs
+++ b/src/Data/Bifunctor/Functor.hs
@@ -2,6 +2,10 @@
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE TypeOperators #-}
 
+#if __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Safe #-}
+#endif
+
 #if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
diff --git a/src/Data/Bifunctor/Join.hs b/src/Data/Bifunctor/Join.hs
--- a/src/Data/Bifunctor/Join.hs
+++ b/src/Data/Bifunctor/Join.hs
@@ -8,6 +8,12 @@
 {-# LANGUAGE DeriveGeneric #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 #if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
diff --git a/src/Data/Bifunctor/Joker.hs b/src/Data/Bifunctor/Joker.hs
--- a/src/Data/Bifunctor/Joker.hs
+++ b/src/Data/Bifunctor/Joker.hs
@@ -11,6 +11,12 @@
 {-# LANGUAGE PolyKinds #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 708
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Copyright   :  (C) 2008-2016 Edward Kmett
diff --git a/src/Data/Bifunctor/Product.hs b/src/Data/Bifunctor/Product.hs
--- a/src/Data/Bifunctor/Product.hs
+++ b/src/Data/Bifunctor/Product.hs
@@ -11,6 +11,12 @@
 {-# LANGUAGE PolyKinds #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 708
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Copyright   :  (C) 2008-2016 Jesse Selover, Edward Kmett
diff --git a/src/Data/Bifunctor/Sum.hs b/src/Data/Bifunctor/Sum.hs
--- a/src/Data/Bifunctor/Sum.hs
+++ b/src/Data/Bifunctor/Sum.hs
@@ -11,6 +11,12 @@
 {-# LANGUAGE PolyKinds #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 708
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 module Data.Bifunctor.Sum where
 
 import Data.Bifunctor
diff --git a/src/Data/Bifunctor/TH.hs b/src/Data/Bifunctor/TH.hs
--- a/src/Data/Bifunctor/TH.hs
+++ b/src/Data/Bifunctor/TH.hs
@@ -2,6 +2,10 @@
 {-# LANGUAGE PatternGuards #-}
 {-# LANGUAGE BangPatterns #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Unsafe #-}
+#endif
+
 #ifndef MIN_VERSION_template_haskell
 #define MIN_VERSION_template_haskell(x,y,z) 1
 #endif
diff --git a/src/Data/Bifunctor/TH/Internal.hs b/src/Data/Bifunctor/TH/Internal.hs
--- a/src/Data/Bifunctor/TH/Internal.hs
+++ b/src/Data/Bifunctor/TH/Internal.hs
@@ -1,5 +1,9 @@
 {-# LANGUAGE CPP #-}
 
+#if __GLASGOW_HASKELL__ >= 704
+{-# LANGUAGE Unsafe #-}
+#endif
+
 {-|
 Module:      Data.Bifunctor.TH.Internal
 Copyright:   (C) 2008-2016 Edward Kmett, (C) 2015-2016 Ryan Scott
diff --git a/src/Data/Bifunctor/Tannen.hs b/src/Data/Bifunctor/Tannen.hs
--- a/src/Data/Bifunctor/Tannen.hs
+++ b/src/Data/Bifunctor/Tannen.hs
@@ -14,6 +14,12 @@
 {-# LANGUAGE PolyKinds #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 708
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Copyright   :  (C) 2008-2016 Edward Kmett
diff --git a/src/Data/Bifunctor/Wrapped.hs b/src/Data/Bifunctor/Wrapped.hs
--- a/src/Data/Bifunctor/Wrapped.hs
+++ b/src/Data/Bifunctor/Wrapped.hs
@@ -11,6 +11,12 @@
 {-# LANGUAGE PolyKinds #-}
 #endif
 
+#if __GLASGOW_HASKELL__ >= 708
+{-# LANGUAGE Safe #-}
+#elif __GLASGOW_HASKELL__ >= 702
+{-# LANGUAGE Trustworthy #-}
+#endif
+
 -----------------------------------------------------------------------------
 -- |
 -- Copyright   :  (C) 2008-2016 Edward Kmett