diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 19acc36..b483954 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         rust: [
-          1.87.0, # MSRV
+          1.90.0, # MSRV
           stable,
           beta,
           nightly,
@@ -52,7 +52,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: dtolnay/rust-toolchain@1.87.0
+      - uses: dtolnay/rust-toolchain@1.90.0
         with:
           components: rustfmt
       - run: cargo fmt --all --check
diff --git a/Cargo.toml b/Cargo.toml
index 9816b48..d2f9cd9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,13 +1,13 @@
 [package]
 name = "num-primitive"
-version = "0.3.0"
+version = "0.3.1"
 description = "Traits for primitive numeric types"
 repository = "https://github.com/rust-num/num-primitive"
 license = "MIT OR Apache-2.0"
 keywords = ["generic", "mathematics", "numerics", "primitive"]
 categories = ["algorithms", "science", "no-std"]
 edition = "2024"
-rust-version = "1.87"
+rust-version = "1.90"
 
 [features]
 default = ["std"]
diff --git a/README.md b/README.md
index 680cbf2..e6b3392 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 [![crate](https://img.shields.io/crates/v/num-primitive.svg)](https://crates.io/crates/num-primitive)
 [![documentation](https://docs.rs/num-primitive/badge.svg)](https://docs.rs/num-primitive)
-[![minimum rustc 1.87](https://img.shields.io/badge/rustc-1.87+-red.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
+[![minimum rustc 1.90](https://img.shields.io/badge/rustc-1.90+-red.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
 [![build status](https://github.com/rust-num/num-primitive/workflows/CI/badge.svg)](https://github.com/rust-num/num-primitive/actions)
 
 Traits for primitive numeric types in Rust.
@@ -61,7 +61,7 @@ Release notes are available in [RELEASES.md](RELEASES.md).
 
 ## Compatibility
 
-The `num-primitive` crate is currently tested for Rust 1.87 and greater. This
+The `num-primitive` crate is currently tested for Rust 1.90 and greater. This
 minimum-supported Rust version (MSRV) may be increased at any time to add
 support for newly-stabilized functionality from the standard library. Changes
 will be documented prominently in the release notes.
diff --git a/RELEASES.md b/RELEASES.md
index 7571666..58a0094 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -1,3 +1,8 @@
+# Release 0.3.1 (2025-12-16)
+
+- Updated to MSRV 1.90.
+- Added `PrimitiveUnsigned::{checked,overflowing,saturating,wrapping}_sub_signed`
+
 # Release 0.3.0 (2025-12-16)
 
 - Added `PrimitiveNumber::midpoint`
diff --git a/src/unsigned.rs b/src/unsigned.rs
index 7614128..8f797ad 100644
--- a/src/unsigned.rs
+++ b/src/unsigned.rs
@@ -56,6 +56,10 @@ pub trait PrimitiveUnsigned: PrimitiveInteger + From<u8> {
     /// wrapped in Some.
     fn checked_next_power_of_two(self) -> Option<Self>;
 
+    /// Checked subtraction with a signed integer. Computes `self - rhs`,
+    /// returning `None` if overflow occurred.
+    fn checked_sub_signed(self, rhs: Self::Signed) -> Option<Self>;
+
     /// Calculates the quotient of `self` and rhs, rounding the result towards positive infinity.
     fn div_ceil(self, rhs: Self) -> Self;
 
@@ -75,13 +79,25 @@ pub trait PrimitiveUnsigned: PrimitiveInteger + From<u8> {
     /// boolean indicating whether an arithmetic overflow would occur.
     fn overflowing_add_signed(self, rhs: Self::Signed) -> (Self, bool);
 
+    /// Calculates `self` - `rhs` with a signed `rhs`. Returns a tuple of the subtraction along
+    /// with a boolean indicating whether an arithmetic overflow would occur.
+    fn overflowing_sub_signed(self, rhs: Self::Signed) -> (Self, bool);
+
     /// Saturating addition with a signed integer. Computes `self + rhs`, saturating at the numeric
     /// bounds instead of overflowing.
     fn saturating_add_signed(self, rhs: Self::Signed) -> Self;
 
+    /// Saturating integer subtraction. Computes `self` - `rhs`, saturating at
+    /// the numeric bounds instead of overflowing.
+    fn saturating_sub_signed(self, rhs: Self::Signed) -> Self;
+
     /// Wrapping (modular) addition with a signed integer. Computes `self + rhs`, wrapping around
     /// at the boundary of the type.
     fn wrapping_add_signed(self, rhs: Self::Signed) -> Self;
+
+    /// Wrapping (modular) subtraction with a signed integer. Computes
+    /// `self - rhs`, wrapping around at the boundary of the type.
+    fn wrapping_sub_signed(self, rhs: Self::Signed) -> Self;
 }
 
 /// Trait for references to primitive unsigned integer types ([`PrimitiveUnsigned`]).
@@ -101,14 +117,18 @@ macro_rules! impl_unsigned {
                 fn checked_add_signed(self, rhs: Self::Signed) -> Option<Self>;
                 fn checked_next_multiple_of(self, rhs: Self) -> Option<Self>;
                 fn checked_next_power_of_two(self) -> Option<Self>;
+                fn checked_sub_signed(self, rhs: Self::Signed) -> Option<Self>;
                 fn div_ceil(self, rhs: Self) -> Self;
                 fn is_multiple_of(self, rhs: Self) -> bool;
                 fn is_power_of_two(self) -> bool;
                 fn next_multiple_of(self, rhs: Self) -> Self;
                 fn next_power_of_two(self) -> Self;
                 fn overflowing_add_signed(self, rhs: Self::Signed) -> (Self, bool);
+                fn overflowing_sub_signed(self, rhs: Self::Signed) -> (Self, bool);
                 fn saturating_add_signed(self, rhs: Self::Signed) -> Self;
+                fn saturating_sub_signed(self, rhs: Self::Signed) -> Self;
                 fn wrapping_add_signed(self, rhs: Self::Signed) -> Self;
+                fn wrapping_sub_signed(self, rhs: Self::Signed) -> Self;
             }
         }