diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index c6680623..a77373f6 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -14,8 +14,10 @@ jobs:
       matrix:
         rust: [
           1.31.0, # 2018!
-          1.34.0, # quickcheck, has_try_from
+          1.34.0, # has_try_from
           1.36.0, # alloc, rand
+          1.40.0, # arbitrary
+          1.46.0, # quickcheck
           stable,
           beta,
           nightly
diff --git a/Cargo.toml b/Cargo.toml
index 6e54ee32..85ba6b14 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -62,12 +62,12 @@ default-features = false
 
 [dependencies.quickcheck]
 optional = true
-version = "0.9"
+version = "1"
 default-features = false
 
 [dependencies.arbitrary]
 optional = true
-version = "0.4"
+version = "1"
 default-features = false
 
 [build-dependencies]
diff --git a/bors.toml b/bors.toml
index 1a5421b0..163c03ab 100644
--- a/bors.toml
+++ b/bors.toml
@@ -2,6 +2,8 @@ status = [
   "Test (1.31.0)",
   "Test (1.34.0)",
   "Test (1.36.0)",
+  "Test (1.40.0)",
+  "Test (1.46.0)",
   "Test (stable)",
   "Test (beta)",
   "Test (nightly)",
diff --git a/ci/big_quickcheck/Cargo.toml b/ci/big_quickcheck/Cargo.toml
index c58f6d47..6002eedb 100644
--- a/ci/big_quickcheck/Cargo.toml
+++ b/ci/big_quickcheck/Cargo.toml
@@ -7,10 +7,10 @@ edition = "2018"
 [dependencies]
 num-integer = "0.1.42"
 num-traits = "0.2.11"
-quickcheck_macros = "0.9"
+quickcheck_macros = "1"
 
 [dependencies.quickcheck]
-version = "0.9"
+version = "1"
 default-features = false
 
 [dependencies.num-bigint]
diff --git a/ci/big_quickcheck/src/lib.rs b/ci/big_quickcheck/src/lib.rs
index 36d52877..4db72f8f 100644
--- a/ci/big_quickcheck/src/lib.rs
+++ b/ci/big_quickcheck/src/lib.rs
@@ -9,7 +9,7 @@
 use num_bigint::{BigInt, BigUint};
 use num_integer::Integer;
 use num_traits::{Num, One, Signed, Zero};
-use quickcheck::{QuickCheck, StdThreadGen, TestResult};
+use quickcheck::{Gen, QuickCheck, TestResult};
 use quickcheck_macros::quickcheck;
 
 #[quickcheck]
@@ -42,8 +42,8 @@ fn quickcheck_signed_eq_symmetric(a: BigInt, b: BigInt) -> bool {
 
 #[test]
 fn quickcheck_arith_primitive() {
-    let gen = StdThreadGen::new(usize::max_value());
-    let mut qc = QuickCheck::with_gen(gen);
+    let gen = Gen::new(usize::max_value());
+    let mut qc = QuickCheck::new().gen(gen);
 
     fn test_unsigned_add_primitive(a: usize, b: usize) -> TestResult {
         let actual = BigUint::from(a) + BigUint::from(b);
@@ -79,11 +79,11 @@ fn quickcheck_arith_primitive() {
         }
     }
 
-    fn test_signed_sub_primitive(a: i128, b: i128) -> bool {
-        if b < a {
-            BigInt::from(a - b) == BigInt::from(a) - BigInt::from(b)
-        } else {
-            BigInt::from(b - a) == BigInt::from(b) - BigInt::from(a)
+    fn test_signed_sub_primitive(a: i128, b: i128) -> TestResult {
+        let actual = BigInt::from(a) - BigInt::from(b);
+        match a.checked_sub(b) {
+            None => TestResult::discard(),
+            Some(expected) => TestResult::from_bool(BigInt::from(expected) == actual),
         }
     }
 
@@ -96,7 +96,7 @@ fn quickcheck_arith_primitive() {
     }
 
     fn test_signed_div_primitive(a: i128, b: i128) -> TestResult {
-        if b == 0 {
+        if b == 0 || (a == i128::MIN && b == -1) {
             TestResult::discard()
         } else {
             TestResult::from_bool(BigInt::from(a / b) == BigInt::from(a) / BigInt::from(b))
@@ -108,7 +108,7 @@ fn quickcheck_arith_primitive() {
     qc.quickcheck(test_unsigned_mul_primitive as fn(u64, u64) -> bool);
     qc.quickcheck(test_signed_mul_primitive as fn(i64, i64) -> bool);
     qc.quickcheck(test_unsigned_sub_primitive as fn(u128, u128) -> bool);
-    qc.quickcheck(test_signed_sub_primitive as fn(i128, i128) -> bool);
+    qc.quickcheck(test_signed_sub_primitive as fn(i128, i128) -> TestResult);
     qc.quickcheck(test_unsigned_div_primitive as fn(u128, u128) -> TestResult);
     qc.quickcheck(test_signed_div_primitive as fn(i128, i128) -> TestResult);
 }
@@ -280,8 +280,8 @@ fn quickcheck_signed_conversion(a: BigInt, radix: u8) -> TestResult {
 
 #[test]
 fn quicktest_shift() {
-    let gen = StdThreadGen::new(usize::max_value());
-    let mut qc = QuickCheck::with_gen(gen);
+    let gen = Gen::new(usize::max_value());
+    let mut qc = QuickCheck::new().gen(gen);
 
     fn test_shr_unsigned(a: u64, shift: u8) -> TestResult {
         let shift = (shift % 64) as usize; //shift at most 64 bits
@@ -317,8 +317,8 @@ fn quicktest_shift() {
 
 #[test]
 fn quickcheck_modpow() {
-    let gen = StdThreadGen::new(usize::max_value());
-    let mut qc = QuickCheck::with_gen(gen);
+    let gen = Gen::new(usize::max_value());
+    let mut qc = QuickCheck::new().gen(gen);
 
     fn simple_modpow(base: &BigInt, exponent: &BigInt, modulus: &BigInt) -> BigInt {
         assert!(!exponent.is_negative());
diff --git a/ci/rustup.sh b/ci/rustup.sh
index ef75c700..607901c0 100755
--- a/ci/rustup.sh
+++ b/ci/rustup.sh
@@ -5,6 +5,6 @@
 set -ex
 
 ci=$(dirname $0)
-for version in 1.31.0 1.34.0 1.36.0 stable beta nightly; do
+for version in 1.31.0 1.34.0 1.36.0 1.40.0 1.46.0 stable beta nightly; do
     rustup run "$version" "$ci/test_full.sh"
 done
diff --git a/ci/test_full.sh b/ci/test_full.sh
index c3e2785f..d84feae8 100755
--- a/ci/test_full.sh
+++ b/ci/test_full.sh
@@ -28,10 +28,10 @@ if ! check_version $MSRV ; then
 fi
 
 STD_FEATURES=(serde)
-check_version 1.34 && STD_FEATURES+=(quickcheck)
 check_version 1.36 && STD_FEATURES+=(rand)
 check_version 1.36 && NO_STD_FEATURES=(serde rand)
 check_version 1.40 && STD_FEATURES+=(arbitrary)
+check_version 1.46 && STD_FEATURES+=(quickcheck)
 echo "Testing supported features: ${STD_FEATURES[*]}"
 if [ -n "${NO_STD_FEATURES[*]}" ]; then
   echo " no_std supported features: ${NO_STD_FEATURES[*]}"
diff --git a/src/bigint.rs b/src/bigint.rs
index 4b0e4891..891eeb46 100644
--- a/src/bigint.rs
+++ b/src/bigint.rs
@@ -59,7 +59,6 @@ impl Neg for Sign {
 }
 
 /// A big signed integer type.
-#[derive(Debug)]
 pub struct BigInt {
     sign: Sign,
     data: BigUint,
@@ -137,6 +136,12 @@ impl Default for BigInt {
     }
 }
 
+impl fmt::Debug for BigInt {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
 impl fmt::Display for BigInt {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.pad_integral(!self.is_negative(), "", &self.data.to_str_radix(10))
diff --git a/src/bigint/arbitrary.rs b/src/bigint/arbitrary.rs
index 08e05f9e..df66050e 100644
--- a/src/bigint/arbitrary.rs
+++ b/src/bigint/arbitrary.rs
@@ -1,11 +1,12 @@
 use super::{BigInt, Sign};
 
+#[cfg(feature = "quickcheck")]
 use crate::std_alloc::Box;
 use crate::BigUint;
 
 #[cfg(feature = "quickcheck")]
 impl quickcheck::Arbitrary for BigInt {
-    fn arbitrary<G: quickcheck::Gen>(g: &mut G) -> Self {
+    fn arbitrary(g: &mut quickcheck::Gen) -> Self {
         let positive = bool::arbitrary(g);
         let sign = if positive { Sign::Plus } else { Sign::Minus };
         Self::from_biguint(sign, BigUint::arbitrary(g))
@@ -19,16 +20,20 @@ impl quickcheck::Arbitrary for BigInt {
 }
 
 #[cfg(feature = "arbitrary")]
-impl arbitrary::Arbitrary for BigInt {
+impl arbitrary::Arbitrary<'_> for BigInt {
     fn arbitrary(u: &mut arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
         let positive = bool::arbitrary(u)?;
         let sign = if positive { Sign::Plus } else { Sign::Minus };
         Ok(Self::from_biguint(sign, BigUint::arbitrary(u)?))
     }
 
-    fn shrink(&self) -> Box<dyn Iterator<Item = Self>> {
-        let sign = self.sign();
-        let unsigned_shrink = self.data.shrink();
-        Box::new(unsigned_shrink.map(move |x| BigInt::from_biguint(sign, x)))
+    fn arbitrary_take_rest(mut u: arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
+        let positive = bool::arbitrary(&mut u)?;
+        let sign = if positive { Sign::Plus } else { Sign::Minus };
+        Ok(Self::from_biguint(sign, BigUint::arbitrary_take_rest(u)?))
+    }
+
+    fn size_hint(depth: usize) -> (usize, Option<usize>) {
+        arbitrary::size_hint::and(bool::size_hint(depth), BigUint::size_hint(depth))
     }
 }
diff --git a/src/biguint.rs b/src/biguint.rs
index b790c57a..42350714 100644
--- a/src/biguint.rs
+++ b/src/biguint.rs
@@ -35,7 +35,6 @@ pub(crate) use self::convert::to_str_radix_reversed;
 pub use self::iter::{U32Digits, U64Digits};
 
 /// A big unsigned integer type.
-#[derive(Debug)]
 pub struct BigUint {
     data: Vec<BigDigit>,
 }
@@ -106,6 +105,12 @@ impl Default for BigUint {
     }
 }
 
+impl fmt::Debug for BigUint {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
 impl fmt::Display for BigUint {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.pad_integral(true, "", &self.to_str_radix(10))
diff --git a/src/biguint/arbitrary.rs b/src/biguint/arbitrary.rs
index 8a2eb9e9..6fa91c0f 100644
--- a/src/biguint/arbitrary.rs
+++ b/src/biguint/arbitrary.rs
@@ -1,11 +1,13 @@
 use super::{biguint_from_vec, BigUint};
 
 use crate::big_digit::BigDigit;
-use crate::std_alloc::{Box, Vec};
+#[cfg(feature = "quickcheck")]
+use crate::std_alloc::Box;
+use crate::std_alloc::Vec;
 
 #[cfg(feature = "quickcheck")]
 impl quickcheck::Arbitrary for BigUint {
-    fn arbitrary<G: quickcheck::Gen>(g: &mut G) -> Self {
+    fn arbitrary(g: &mut quickcheck::Gen) -> Self {
         // Use arbitrary from Vec
         biguint_from_vec(Vec::<BigDigit>::arbitrary(g))
     }
@@ -17,12 +19,16 @@ impl quickcheck::Arbitrary for BigUint {
 }
 
 #[cfg(feature = "arbitrary")]
-impl arbitrary::Arbitrary for BigUint {
+impl arbitrary::Arbitrary<'_> for BigUint {
     fn arbitrary(u: &mut arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
         Ok(biguint_from_vec(Vec::<BigDigit>::arbitrary(u)?))
     }
 
-    fn shrink(&self) -> Box<dyn Iterator<Item = Self>> {
-        Box::new(self.data.shrink().map(biguint_from_vec))
+    fn arbitrary_take_rest(u: arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
+        Ok(biguint_from_vec(Vec::<BigDigit>::arbitrary_take_rest(u)?))
+    }
+
+    fn size_hint(depth: usize) -> (usize, Option<usize>) {
+        Vec::<BigDigit>::size_hint(depth)
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index bfca016c..a4ab704a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -94,7 +94,7 @@ extern crate std;
 #[cfg(feature = "std")]
 mod std_alloc {
     pub(crate) use std::borrow::Cow;
-    #[cfg(any(feature = "quickcheck", feature = "arbitrary"))]
+    #[cfg(any(feature = "quickcheck"))]
     pub(crate) use std::boxed::Box;
     pub(crate) use std::string::String;
     pub(crate) use std::vec::Vec;
@@ -107,7 +107,7 @@ extern crate alloc;
 #[cfg(not(feature = "std"))]
 mod std_alloc {
     pub(crate) use alloc::borrow::Cow;
-    #[cfg(any(feature = "quickcheck", feature = "arbitrary"))]
+    #[cfg(any(feature = "quickcheck"))]
     pub(crate) use alloc::boxed::Box;
     pub(crate) use alloc::string::String;
     pub(crate) use alloc::vec::Vec;