diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,12 +1,12 @@
 # Revision history for rounded
 
-## 0.3 -- 2020-05-19
+## 1.0 -- 2019-08-28
 
-* Fixed `simplify` with `Nat` precisions by adding kind signatures.
+* Require MPFR 4.0 or above.
 
 ## 0.2 -- 2019-08-28
 
-* Wrapped a lot more of the MPFR API.
+* Wrapped a lot more of the MPFR 3.1 API.
 * Fixed `wrapped_mpfr_set_ld()` FFI binding.  Previously `fromLongDouble`
   could corrupt memory or crash due to missing argument.
 * Removed dependency on `singletons`.
diff --git a/rounded.cabal b/rounded.cabal
--- a/rounded.cabal
+++ b/rounded.cabal
@@ -1,5 +1,5 @@
 name:               rounded
-version:            0.3
+version:            1.0
 synopsis:           Correctly-rounded arbitrary-precision floating-point arithmetic
 homepage:           https://github.com/ekmett/rounded
 bug-reports:        https://github.com/ekmett/rounded/issues
@@ -28,7 +28,7 @@
     >>> exp pi :: Rounded TowardZero 512
     23.140692632779269005729086367948547380266106242600211993445046409524342350690452783516971997067549219675952704801087773144428044414693835844717445879609842
     .
-    rounded version 0.x is for MPFR version 3.1 or above.
+    rounded version 1.x is for MPFR version 4.0 and above.
 
 extra-source-files: README.markdown CHANGELOG.markdown test.hs test.txt
 
@@ -39,7 +39,7 @@
 source-repository this
   type: git
   location: git://github.com/ekmett/rounded.git
-  tag: rounded-0.3
+  tag: rounded-1.0
 
 library
   exposed-modules:
@@ -57,8 +57,8 @@
     Numeric.Rounded.Precision
 
   build-depends:
-    base             >= 4.8     && < 4.15,
-    ghc-prim         >= 0.4     && < 0.7,
+    base             >= 4.8     && < 4.14,
+    ghc-prim         >= 0.4     && < 0.6,
     reflection       >= 2.1.2   && < 2.2,
     hgmp             >= 0.1.1   && < 0.2,
     long-double      >= 0.1     && < 0.2
@@ -67,6 +67,7 @@
   build-tools:     hsc2hs
 
   extra-libraries: mpfr gmp
+  pkgconfig-depends: mpfr >= 4.0.0
 
   hs-source-dirs:  src
   c-sources:       cbits/wrappers.c
diff --git a/src/Numeric/MPFR/Raw/Safe.hs b/src/Numeric/MPFR/Raw/Safe.hs
--- a/src/Numeric/MPFR/Raw/Safe.hs
+++ b/src/Numeric/MPFR/Raw/Safe.hs
@@ -146,6 +146,9 @@
 foreign import ccall safe "mpfr_pow" mpfr_pow :: Binary
 foreign import ccall safe "mpfr_sub" mpfr_sub :: Binary
 
+foreign import ccall safe "mpfr_beta" mpfr_beta :: Binary
+foreign import ccall safe "mpfr_gamma_inc" mpfr_gamma_inc :: Binary
+
 type DualOutput = Ptr MPFR -> Ptr MPFR -> Ptr MPFR -> MPFRRnd -> IO CInt
 
 foreign import ccall safe "mpfr_modf" mpfr_modf :: DualOutput
diff --git a/src/Numeric/MPFR/Raw/Unsafe.hs b/src/Numeric/MPFR/Raw/Unsafe.hs
--- a/src/Numeric/MPFR/Raw/Unsafe.hs
+++ b/src/Numeric/MPFR/Raw/Unsafe.hs
@@ -146,6 +146,9 @@
 foreign import ccall unsafe "mpfr_pow" mpfr_pow :: Binary
 foreign import ccall unsafe "mpfr_sub" mpfr_sub :: Binary
 
+foreign import ccall unsafe "mpfr_beta" mpfr_beta :: Binary
+foreign import ccall unsafe "mpfr_gamma_inc" mpfr_gamma_inc :: Binary
+
 type DualOutput = Ptr MPFR -> Ptr MPFR -> Ptr MPFR -> MPFRRnd -> IO CInt
 
 foreign import ccall unsafe "mpfr_modf" mpfr_modf :: DualOutput
diff --git a/src/Numeric/Rounded.hs b/src/Numeric/Rounded.hs
--- a/src/Numeric/Rounded.hs
+++ b/src/Numeric/Rounded.hs
@@ -110,6 +110,8 @@
     , mul_
     , pow_
     , sub_
+    , beta_
+    , gamma_inc_
     -- ** Dual output
     , modf
     , sin_cos
diff --git a/src/Numeric/Rounded/Internal.hs b/src/Numeric/Rounded/Internal.hs
--- a/src/Numeric/Rounded/Internal.hs
+++ b/src/Numeric/Rounded/Internal.hs
@@ -244,7 +244,7 @@
         f cfr afr bfr (rnd a)
   return c
 
-add_, agm_, atan2_, copysign_, dim_, div_, fmod_, hypot_, max_, min_, mul_, pow_, sub_,
+add_, agm_, atan2_, copysign_, dim_, div_, fmod_, hypot_, max_, min_, mul_, pow_, sub_, beta_, gamma_inc_,
  (!+!), (!-!), (!*!), (!/!), (!**!)
   :: (Rounding r, Precision p1, Precision p2, Precision p3)
   => Rounded r p1 -> Rounded r p2 -> Rounded r p3
@@ -261,6 +261,8 @@
 mul_ = binary mpfr_mul
 pow_ = binary mpfr_pow
 sub_ = binary mpfr_sub
+beta_ = binary mpfr_beta
+gamma_inc_ = binary mpfr_gamma_inc
 (!+!) = add_
 (!-!) = sub_
 (!*!) = mul_
diff --git a/src/Numeric/Rounded/Simple.hs b/src/Numeric/Rounded/Simple.hs
--- a/src/Numeric/Rounded/Simple.hs
+++ b/src/Numeric/Rounded/Simple.hs
@@ -1,6 +1,5 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE MagicHash #-}
-{-# LANGUAGE PolyKinds #-}
 {-# LANGUAGE RankNTypes #-}
 -----------------------------------------------------------------------------
 -- |
@@ -142,6 +141,8 @@
   , dim_
   , fmod_
   , hypot_
+  , beta_
+  , gamma_inc_
   -- * Foreign Function Interface
   , withInRounded
   , withInOutRounded
@@ -176,16 +177,16 @@
 precision :: Rounded -> Precision
 precision = fromIntegral . roundedPrec
 
-reifyRounded :: Rounded -> (forall k (p :: k) . R.Precision p => R.Rounded r p -> a) -> a
+reifyRounded :: Rounded -> (forall p . R.Precision p => R.Rounded r p -> a) -> a
 reifyRounded (Rounded p s e l) f = R.reifyPrecision (fromIntegral p) (\q -> f (g q (R.Rounded p s e l)))
   where
     g :: R.Precision q => proxy q -> R.Rounded s q -> R.Rounded s q
     g _ x = x
 
-simplify :: forall r k (p :: k) . R.Rounded r p -> Rounded
+simplify :: R.Rounded r p -> Rounded
 simplify (R.Rounded p s e l) = Rounded p s e l
 
-constant :: (forall r k (p :: k) . (R.Rounding r, R.Precision p) => R.Rounded r p) -> RoundingMode -> Precision -> Rounded
+constant :: (forall r p . (R.Rounding r, R.Precision p) => R.Rounded r p) -> RoundingMode -> Precision -> Rounded
 constant f r q = R.reifyRounding r (\pr -> R.reifyPrecision q (\pq -> g pr pq f))
   where
     g :: (R.Rounding r, R.Precision p) => proxy1 r -> proxy2 p -> R.Rounded r p -> Rounded
@@ -198,7 +199,7 @@
 kEuler = constant R.kEuler
 kCatalan = constant R.kCatalan
 
-unary :: (forall r kp (p :: kp) kq (q :: kq) . (R.Rounding r, R.Precision p, R.Precision q) => R.Rounded r p -> R.Rounded r q) -> RoundingMode -> Precision -> Rounded -> Rounded
+unary :: (forall r p q . (R.Rounding r, R.Precision p, R.Precision q) => R.Rounded r p -> R.Rounded r q) -> RoundingMode -> Precision -> Rounded -> Rounded
 unary f r q a = R.reifyRounding r (\pr -> R.reifyPrecision q (\pq -> reifyRounded a (\ra -> g pr pq f ra)))
   where
     g :: (R.Rounding r, R.Precision p, R.Precision q) => proxy1 r -> proxy2 q -> (R.Rounded r p -> R.Rounded r q) -> R.Rounded r p -> Rounded
@@ -277,22 +278,22 @@
 fromRational' :: RoundingMode -> Precision -> Rational -> Rounded
 fromRational' = fromX fromRational
 
-fromX :: (forall r k (p :: k) . (R.Rounding r, R.Precision p) => x -> R.Rounded r p) -> RoundingMode -> Precision -> x -> Rounded
+fromX :: (forall r p . (R.Rounding r, R.Precision p) => x -> R.Rounded r p) -> RoundingMode -> Precision -> x -> Rounded
 fromX f r p x = R.reifyRounding r (\pr -> R.reifyPrecision p (\pp -> g pr pp (f x)))
   where
     g :: (R.Rounding r, R.Precision p) => proxy1 r -> proxy2 p -> R.Rounded r p -> Rounded
-    g _ _ y = simplify y
+    g _ _ x = simplify x
 
-binary :: (forall r kp (p :: kp) kq (q :: kq) kpq (pq :: kpq) . (R.Rounding r, R.Precision p, R.Precision q, R.Precision pq) => R.Rounded r p -> R.Rounded r q -> R.Rounded r pq) -> RoundingMode -> Precision -> Rounded -> Rounded -> Rounded
+binary :: (forall r p q pq . (R.Rounding r, R.Precision p, R.Precision q, R.Precision pq) => R.Rounded r p -> R.Rounded r q -> R.Rounded r pq) -> RoundingMode -> Precision -> Rounded -> Rounded -> Rounded
 binary f r pq a b = R.reifyRounding r (\pr -> R.reifyPrecision pq (\ppq -> reifyRounded a (\ra -> reifyRounded b (\rb -> g pr ppq f ra rb))))
   where
     g :: (R.Rounding r, R.Precision p, R.Precision q, R.Precision pq) => proxy1 r -> proxy2 pq -> (R.Rounded r p -> R.Rounded r q -> R.Rounded r pq) -> R.Rounded r p -> R.Rounded r q -> Rounded
     g _ _ h x y = simplify (h x y)
 
-binary' :: (forall r kp (p :: kp) kq (q :: kq) kpq (pq :: kpq) . (R.Rounding r, R.Precision p, R.Precision q, R.Precision pq) => R.Rounded r p -> R.Rounded r q -> R.Rounded r pq) -> Rounded -> Rounded -> Rounded
+binary' :: (forall r p q pq . (R.Rounding r, R.Precision p, R.Precision q, R.Precision pq) => R.Rounded r p -> R.Rounded r q -> R.Rounded r pq) -> Rounded -> Rounded -> Rounded
 binary' f a b = binary f R.TowardNearest (precision a `max` precision b) a b
 
-add_, agm_, atan2_, copysign_, dim_, div_, fmod_, hypot_, max_, min_, mul_, pow_, sub_
+add_, agm_, atan2_, copysign_, dim_, div_, fmod_, hypot_, max_, min_, mul_, pow_, sub_, beta_, gamma_inc_
   :: RoundingMode -> Precision -> Rounded -> Rounded -> Rounded
 add_ = binary R.add_
 agm_ = binary R.agm_
@@ -307,14 +308,16 @@
 mul_ = binary R.mul_
 pow_ = binary R.pow_
 sub_ = binary R.sub_
+beta_ = binary R.beta_
+gamma_inc_ = binary R.gamma_inc_
 
-unary' :: (forall r k (p :: k) . (R.Rounding r, R.Precision p) => R.Rounded r p -> a) -> RoundingMode -> Rounded -> a
+unary' :: (forall r p . (R.Rounding r, R.Precision p) => R.Rounded r p -> a) -> RoundingMode -> Rounded -> a
 unary' f r a = R.reifyRounding r (\pr -> reifyRounded a (\ra -> g pr f ra))
   where
     g :: (R.Rounding r, R.Precision p) => proxy r -> (R.Rounded r p -> a) -> R.Rounded r p -> a
     g _ h x = h x
 
-unary'' :: (forall r k (p :: k) . (R.Rounding r, R.Precision p) => R.Rounded r p -> a) -> Rounded -> a
+unary'' :: (forall r p . (R.Rounding r, R.Precision p) => R.Rounded r p -> a) -> Rounded -> a
 unary'' f a = unary' f R.TowardNearest a
 
 toDouble :: RoundingMode -> Rounded -> Double
@@ -391,7 +394,7 @@
 
 type Comparison = Rounded -> Rounded -> Bool
 
-cmp :: (forall kp (p :: kp) kq (q :: kq) . (R.Precision p, R.Precision q) => R.Rounded R.TowardNearest p -> R.Rounded R.TowardNearest q -> Bool) -> Comparison
+cmp :: (forall p q . (R.Precision p, R.Precision q) => R.Rounded R.TowardNearest p -> R.Rounded R.TowardNearest q -> Bool) -> Comparison
 cmp f a b = reifyRounded a (\ra -> reifyRounded b (\rb -> f ra rb))
 
 instance Eq Rounded where