diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 26f1792..a823415 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,6 +23,19 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - run: cargo check
 
+  msrv:
+    name: MSRV
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@1.88.0
+      - uses: Swatinem/rust-cache@v2
+      # The MSRV is a promise about the library, so this checks `--lib` only:
+      # tests and benches pull in dev-dependencies, which track their own,
+      # newer minimum toolchain. Keep the pinned version in sync with
+      # `rust-version` in `Cargo.toml`.
+      - run: cargo check --lib --locked
+
   fmt:
     name: Format
     runs-on: ubuntu-latest
diff --git a/Cargo.toml b/Cargo.toml
index 6a5e350..41e7310 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,6 +2,7 @@
 name = "netip"
 version = "0.3.7"
 edition = "2024"
+rust-version = "1.88"
 license = "Apache-2.0"
 description = "IPv4/IPv6 network types with non-contiguous masks support"
 repository = "https://github.com/yanet-platform/netip"
diff --git a/README.md b/README.md
index c5c004b..570e7ae 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,7 @@
 
 [![crates.io](https://img.shields.io/crates/v/netip.svg)](https://crates.io/crates/netip)
 [![docs.rs](https://docs.rs/netip/badge.svg)](https://docs.rs/netip)
+[![MSRV](https://img.shields.io/badge/MSRV-1.88-blue.svg)](#minimum-supported-rust-version)
 [![License](https://img.shields.io/crates/l/netip.svg)](LICENSE)
 
 **Zero-dependency** Rust library for IPv4/IPv6 networks and MAC addresses — with first-class support for **non-contiguous subnet masks**.
@@ -184,13 +185,19 @@ let mac = MacAddr::parse_ascii(b"aa-bb-cc-dd-ee-ff").unwrap();
 | `BiContiguous<Ipv6Network>` | Newtype for two-run IPv6 masks — one contiguous prefix per 64-bit half |
 | `MacAddr` | MAC address (EUI-48), stored as lower 48 bits of `u64` |
 
+## Minimum Supported Rust Version
+
+`netip` compiles on **Rust 1.88** and newer, checked in CI on every pull request against that exact toolchain.
+
+Raising the MSRV is treated as a breaking change: it ships in a minor version bump (`0.x`), never in a patch release.
+
 ## Roadmap
 
 `netip` is on the path to a stable 1.0. Current version: **0.3.7**.
 
 - ~~**v0.3** — API cleanup, set-algebra completion, `Contiguous`/`BiContiguous` wrappers, slice aggregation, fast ASCII parsers, `no_std`, performance campaigns~~ ✓
 - **v0.4** — API freeze, the last breaking release: `#[non_exhaustive]` error types, by-value getters. Additive alongside it: non-string constructors for `Contiguous<T>`, `FusedIterator` on the iterators, `IpNetwork` method parity
-- **v0.5+** — Testing hardening and documentation: an independent oracle for the network grammar, non-contiguous coverage across every operation, declared MSRV
+- **v0.5+** — Testing hardening and documentation: an independent oracle for the network grammar, non-contiguous coverage across every operation
 - **v1.0** — Stable release
 
 ## License