diff --git a/.github/workflows/sdp-types.yml b/.github/workflows/sdp-types.yml
index 808afd3..917c0f6 100644
--- a/.github/workflows/sdp-types.yml
+++ b/.github/workflows/sdp-types.yml
@@ -42,7 +42,7 @@ jobs:
 
     strategy:
       matrix:
-        toolchain: [stable, beta, nightly]
+        toolchain: ['1.65', stable, beta, nightly]
 
     steps:
     - uses: actions/checkout@v2
@@ -54,6 +54,10 @@ jobs:
         toolchain: ${{ matrix.toolchain }}
         override: true
 
+    - name: Use MSRV Cargo.lock
+      run: cp Cargo.lock.msrv Cargo.lock
+      if: matrix.toolchain == '1.65'
+
     - name: Run tests
       run: |
         cargo test
diff --git a/Cargo.lock.msrv b/Cargo.lock.msrv
new file mode 100644
index 0000000..f4b1973
--- /dev/null
+++ b/Cargo.lock.msrv
@@ -0,0 +1,32 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "bstr"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c48f0051a4b4c5e0b6d365cd04af53aeaa209e3cc15ec2cdb69e73cc87fbd0dc"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "fallible-iterator"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2acce4a10f12dc2fb14a218589d4f1f62ef011b2d0cc4b3cb1bba8e94da14649"
+
+[[package]]
+name = "memchr"
+version = "2.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "523dc4f511e55ab87b694dc30d0f820d60906ef06413f93d4d7a1385599cc149"
+
+[[package]]
+name = "sdp-types"
+version = "0.1.5"
+dependencies = [
+ "bstr",
+ "fallible-iterator",
+]