diff --git a/.github/workflows/rust.yaml b/.github/workflows/rust.yaml
index e705c62..d80ba45 100644
--- a/.github/workflows/rust.yaml
+++ b/.github/workflows/rust.yaml
@@ -20,7 +20,7 @@ jobs:
         id: read_toolchain
         run: echo "nightly_version=$(cat nightly-version)" >> $GITHUB_OUTPUT
 
-  Stable:                       # 2 jobs, one per manifest.
+  Stable:                       # 2 jobs, one per lock file.
     name: Test - stable toolchain
     runs-on: ubuntu-latest
     strategy:
@@ -43,7 +43,7 @@ jobs:
       - name: "Run test script"
         run: ./maintainer-tools/ci/run_task.sh stable
 
-  Nightly:                      # 2 jobs, one per manifest.
+  Nightly:                      # 2 jobs, one per lock file.
     name: Test - nightly toolchain
     needs: Prepare
     runs-on: ubuntu-latest
@@ -69,6 +69,30 @@ jobs:
       - name: "Run test script"
         run: ./maintainer-tools/ci/run_task.sh nightly
 
+  MSRV:                         # 2 jobs, one per lock file.
+    name: Test - 1.56.1 toolchain
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        dep: [minimal, recent]
+    steps:
+      - name: "Checkout repo"
+        uses: actions/checkout@v4
+      - name: "Checkout maintainer tools"
+        uses: actions/checkout@v4
+        with:
+          repository: rust-bitcoin/rust-bitcoin-maintainer-tools
+          path: maintainer-tools
+      - name: "Select toolchain"
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: "1.56.1"
+      - name: "Set dependencies"
+        run: cp Cargo-${{ matrix.dep }}.lock Cargo.lock
+      - name: "Run test script"
+        run: ./maintainer-tools/ci/run_task.sh msrv
+
   Lint:
     name: Lint - nightly toolchain
     needs: Prepare
diff --git a/Cargo-minimal.lock b/Cargo-minimal.lock
index b4b9bd5..7947646 100644
--- a/Cargo-minimal.lock
+++ b/Cargo-minimal.lock
@@ -108,9 +108,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.0.98"
+version = "1.0.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41c270e7540d725e65ac7f1b212ac8ce349719624d7bcff99f8e2e488e8cf03f"
+checksum = "bb4a8b715cb4597106ea87c7c84b2f1d452c7492033765df7f32651e66fcf749"
 
 [[package]]
 name = "hex-conservative"
@@ -147,9 +147,9 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.21"
+version = "0.4.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90ed8c1e510134f979dbc4f070f87d4313098b704861a105fe34231c70a3901c"
+checksum = "518ef76f2f87365916b142844c16d8fefd85039bc5699050210a7778ee1cd1de"
 
 [[package]]
 name = "minreq"
@@ -239,9 +239,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.66"
+version = "2.0.56"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c42f3f41a2de00b01c0aaad383c5a45241efc8b2d1eda5661812fda5f3cdcff5"
+checksum = "6e2415488199887523e74fd9a5f7be804dfd42d868ae0eca382e3917094d210e"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -250,6 +250,6 @@ dependencies = [
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.12"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
+checksum = "e5464a87b239f13a63a501f2701565754bae92d243d4bb7eb12f6d57d2269bf4"
diff --git a/Cargo-recent.lock b/Cargo-recent.lock
index b4b9bd5..7947646 100644
--- a/Cargo-recent.lock
+++ b/Cargo-recent.lock
@@ -108,9 +108,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.0.98"
+version = "1.0.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41c270e7540d725e65ac7f1b212ac8ce349719624d7bcff99f8e2e488e8cf03f"
+checksum = "bb4a8b715cb4597106ea87c7c84b2f1d452c7492033765df7f32651e66fcf749"
 
 [[package]]
 name = "hex-conservative"
@@ -147,9 +147,9 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.21"
+version = "0.4.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90ed8c1e510134f979dbc4f070f87d4313098b704861a105fe34231c70a3901c"
+checksum = "518ef76f2f87365916b142844c16d8fefd85039bc5699050210a7778ee1cd1de"
 
 [[package]]
 name = "minreq"
@@ -239,9 +239,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.66"
+version = "2.0.56"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c42f3f41a2de00b01c0aaad383c5a45241efc8b2d1eda5661812fda5f3cdcff5"
+checksum = "6e2415488199887523e74fd9a5f7be804dfd42d868ae0eca382e3917094d210e"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -250,6 +250,6 @@ dependencies = [
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.12"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
+checksum = "e5464a87b239f13a63a501f2701565754bae92d243d4bb7eb12f6d57d2269bf4"