diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 03c99a1..628ec96 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -57,7 +57,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        rust: [1.65.0, 1.66.0]
+        rust: [1.63.0, 1.64.0]
     timeout-minutes: 45
     steps:
       - uses: actions/checkout@v4
@@ -69,8 +69,23 @@ jobs:
       - run: cargo test --no-default-features
       - run: cargo test --no-default-features --features serde_no_std
       - run: cargo test --features serde
-      - run: cargo test --features borsh
       - run: cargo test --features miniserde
+
+  msrv-borsh:
+    name: Rust ${{matrix.rust}}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        rust: [1.67.0, 1.68.0]
+    timeout-minutes: 45
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{matrix.rust}}
+      - run: cargo test
+      - run: cargo test --features borsh
       - run: cargo test --features nanoserde
       - run: cargo test --features nanoserde --no-default-features
 
diff --git a/Cargo.toml b/Cargo.toml
index 4537016..05fbd36 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,7 @@ documentation = "https://docs.rs/bit-set/"
 keywords = ["data-structures", "bitset"]
 readme = "README.md"
 edition = "2021"
-rust-version = "1.65"
+rust-version = "1.63"
 
 [dependencies]
 borsh = { version = "1.5", default-features = false, features = ["derive"], optional = true }
diff --git a/README.md b/README.md
index dd6ed92..d7e96a9 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,9 @@
 [![crates.io][crates.io shield]][crates.io link]
 [![Documentation][docs.rs badge]][docs.rs link]
 ![Rust CI][github ci badge]
-![rustc 1.65+]
+![rustc 1.63+]
+![borsh: rustc 1.67+]
+![nanoserde: rustc 1.67+]
 <br />
 <br />
 [![Dependency Status][deps.rs status]][deps.rs link]
@@ -22,7 +24,9 @@
 [docs.rs badge]: https://docs.rs/bit-set/badge.svg?version=0.8.0
 [docs.rs link]: https://docs.rs/bit-set/0.8.0/bit_set/
 [github ci badge]: https://github.com/contain-rs/bit-set/workflows/Rust/badge.svg?branch=master
-[rustc 1.65+]: https://img.shields.io/badge/rustc-1.65%2B-blue.svg
+[rustc 1.63+]: https://img.shields.io/badge/rustc-1.63%2B-blue.svg
+[borsh: rustc 1.67+]: https://img.shields.io/badge/borsh:%20rustc-1.67%2B-blue.svg
+[nanoserde: rustc 1.67+]: https://img.shields.io/badge/nanoserde:%20rustc-1.67%2B-blue.svg
 [deps.rs status]: https://deps.rs/crate/bit-set/0.8.0/status.svg
 [deps.rs link]: https://deps.rs/crate/bit-set/0.8.0
 [shields.io download count]: https://img.shields.io/crates/d/bit-set.svg