diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 2e7d3d3a..6aeb8d20 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -1,62 +1,87 @@
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - master
+      - 'test-ci/**'
+  pull_request:
 
 name: Continuous integration
 
 jobs:
-    tests:
-        name: Tests
-        runs-on: ubuntu-latest
-        strategy:
-            matrix:
-                include:
-                    - rust: stable
-                      env:
-                          RUSTFMTCHK: true
-                    - rust: nightly
-                      env:
-                          RUSTFMTCHK: false
-                    - rust: 1.56.1
-                      env:
-                          RUSTFMTCHK: false
-        steps:
-            - name: Checkout Crate
-              uses: actions/checkout@v2
-            - name: Checkout Toolchain
-              uses: actions-rs/toolchain@v1
-              with:
-                  profile: minimal
-                  toolchain: ${{ matrix.rust }}
-                  override: true
-            - name: Running test script
-              env: ${{ matrix.env }}
-              run: ./contrib/test.sh
+  Stable:
+    name: Test - stable toolchain
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - name: "Checkout repo"
+        uses: actions/checkout@v4
+      - name: "Select toolchain"
+        uses: dtolnay/rust-toolchain@stable
+      - name: "Run test script"
+        run: ./contrib/run_task.sh stable
 
-    integrations-tests:
-        name: Integration Tests
-        runs-on: ubuntu-latest
-        strategy:
-            matrix:
-                rust: [stable]
-                bitcoinversion:
-                    [
-                        "0.18.0",
-                        "0.18.1",
-                        "0.19.0.1",
-                        "0.19.1",
-                        "0.20.0",
-                        "0.20.1",
-                        "0.21.0",
-                    ]
-        steps:
-            - name: Checkout Crate
-              uses: actions/checkout@v2
-            - name: Checkout Toolchain
-              uses: actions-rs/toolchain@v1
-              with:
-                  profile: minimal
-                  toolchain: ${{ matrix.rust }}
-                  override: true
-            - name: Running test script
-              env:
-                  BITCOINVERSION: ${{ matrix.bitcoinversion }}
-              run: ./contrib/test.sh
+  Nightly:
+    name: Test - nightly toolchain
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - name: "Checkout repo"
+        uses: actions/checkout@v4
+      - name: "Select toolchain"
+        uses: dtolnay/rust-toolchain@nightly
+      - name: "Run test script"
+        run: ./contrib/run_task.sh nightly
+
+  MSRV:
+    name: Test - 1.56.1 toolchain
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - name: "Checkout repo"
+        uses: actions/checkout@v4
+      - name: "Select toolchain"
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: "1.56.1"
+      - name: "Run test script"
+        run: ./contrib/run_task.sh msrv
+
+  Format:
+    name: Format - nightly toolchain
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - name: "Checkout repo"
+        uses: actions/checkout@v4
+      - name: "Select toolchain"
+        uses: dtolnay/rust-toolchain@stable
+      - name: "Check formatting"
+        run: cargo fmt --all -- --check
+
+  Integration:
+    name: Integration Tests - stable toolchain
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        bitcoin_version:
+          [
+            "0.18.0",
+            "0.18.1",
+            "0.19.0.1",
+            "0.19.1",
+            "0.20.0",
+            "0.20.1",
+            "0.21.0",
+          ]
+    steps:
+      - name: "Checkout repo"
+        uses: actions/checkout@v4
+      - name: "Select toolchain"
+        uses: dtolnay/rust-toolchain@stable
+      - name: Running test script
+        run: ./contrib/run_task.sh integration ${{ matrix.bitcoin_version }}
diff --git a/client/Cargo.toml b/client/Cargo.toml
index cb2573d1..1ec555d2 100644
--- a/client/Cargo.toml
+++ b/client/Cargo.toml
@@ -25,9 +25,9 @@ log = "0.4.5"
 jsonrpc = "0.14.0"
 
 # Used for deserialization of JSON.
-serde = "1"
-serde_json = "1"
+serde = "1.0.156"
+serde_json = "1.0.96"
 
 [dev-dependencies]
-tempfile = "3.3.0"
+tempfile = "3.6.0"
 
diff --git a/contrib/run_task.sh b/contrib/run_task.sh
new file mode 100755
index 00000000..97d3dde0
--- /dev/null
+++ b/contrib/run_task.sh
@@ -0,0 +1,149 @@
+#!/usr/bin/env bash
+#
+# Run CI task, called by the `rust.yml` GitHub action.
+
+set -euo pipefail
+
+REPO_DIR=$(git rev-parse --show-toplevel)
+MSRV="1.56.1"
+
+usage() {
+    cat <<EOF
+Usage: 
+
+    ./run_task.sh TASK
+
+TASK
+  - stable	    Run stable toolchain tests.
+  - nightly    	    Run nightly toolchain tests.
+  - msrv            Run MSRV toolchain tests.
+  - fmt             Run the formatter (rustfmt).
+  - integration     Run integration test for specific Bitcoin Core version.
+
+    ./run_task.sh integration BITCOIN_CORE_VERSION [DOWNLOAD_CORE]
+
+Example
+    ./run_task.sh integration          # Runs integration tests against bitcoind from your path.
+    ./run_task.sh integration 0.21.0   # Downloads Core version 0.21.0 and runs integration tests againts it. 
+
+EOF
+}
+
+# Make all cargo invocations verbose.
+export CARGO_TERM_VERBOSE=true
+
+main() {
+    local task="${1:-usage}"
+    local bitcoin_version="${2:-none}"
+
+    if [ "$task" = "usage" ] || [ "$task" = "-h" ] || [ "$task" = "--help" ]; then
+        usage
+        exit 0
+    fi
+
+    check_required_commands
+
+    cargo --version
+    rustc --version
+    /usr/bin/env bash --version
+    locale
+    env
+
+    case $task in
+	stable)
+            build_and_test "+stable"
+            ;;
+
+	nightly)
+            build_and_test "+nightly"
+            ;;
+
+	msrv)
+            do_msrv_pins
+            build_and_test "+$MSRV"
+            ;;
+
+        fmt)
+            do_fmt
+            ;;
+
+        integration)
+            integration "$bitcoin_version"
+            ;;
+
+        *)
+            echo ""
+            usage
+            err "Error: unknown task $task"
+            ;;
+    esac
+}
+
+# Build and test workspace.
+build_and_test() {
+    local toolchain="$1"
+
+    for crate in json client integration_test; do
+        pushd "$REPO_DIR/$crate" > /dev/null;
+
+        cargo "$toolchain" build
+        cargo "$toolchain" test
+
+        popd > /dev/null
+    done
+}
+
+# Pin dependencies to get the MSRV build to work.
+do_msrv_pins() {
+    cargo update -p tempfile --precise 3.6.0
+    cargo update -p cc --precise 1.0.79
+    cargo update -p log --precise 0.4.18
+    cargo update -p serde_json --precise 1.0.96
+    cargo update -p serde --precise 1.0.156
+}
+
+# Check the workspace formatting.
+do_fmt() {
+    cargo +stable fmt --all --check
+}
+
+# Pulls down Bitcoin Core binary and runs the integration tests.
+integration() {
+    local core_version="$1"
+
+    cd "$REPO_DIR"
+
+    if [ "$core_version" != "none" ]; then
+        wget "https://bitcoincore.org/bin/bitcoin-core-$bitcoin_version/bitcoin-$bitcoin_version-x86_64-linux-gnu.tar.gz"
+        tar -xzvf "bitcoin-$bitcoin_version-x86_64-linux-gnu.tar.gz"
+        export PATH=$PATH:"$REPO_DIR/bitcoin-$bitcoin_version/bin"
+    fi
+
+    need_cmd "bitcoind"
+
+    cd "$REPO_DIR/integration_test"
+    ./run.sh
+}
+
+# Check all the commands we use are present in the current environment.
+check_required_commands() {
+    need_cmd cargo
+    need_cmd rustc
+}
+
+need_cmd() {
+    if ! command -v "$1" > /dev/null 2>&1
+    then err "need '$1' (command not found)"
+    fi
+}
+
+err() {
+    echo "$1" >&2
+    exit 1
+}
+
+#
+# Main script
+#
+main "$@"
+exit 0
diff --git a/contrib/test.sh b/contrib/test.sh
deleted file mode 100755
index e308ce3c..00000000
--- a/contrib/test.sh
+++ /dev/null
@@ -1,35 +0,0 @@
-
-set -xe
-
-MSRV="1\.56"
-
-# Just echo all the relevant env vars to help debug Travis.
-echo "RUSTFMTCHECK: \"$RUSTFMTCHECK\""
-echo "BITCOINVERSION: \"$BITCOINVERSION\""
-echo "PATH: \"$PATH\""
-
-if [ -n "$RUSTFMTCHECK" ]; then
-  rustup component add rustfmt
-  cargo fmt --all -- --check
-fi
-
-# Test pinned versions.
-if cargo --version | grep ${MSRV}; then
-    cargo update -p tempfile --precise 3.3.0
-    cargo update -p log --precise 0.4.18
-fi
-
-# Integration test.
-if [ -n "$BITCOINVERSION" ]; then
-    wget https://bitcoincore.org/bin/bitcoin-core-$BITCOINVERSION/bitcoin-$BITCOINVERSION-x86_64-linux-gnu.tar.gz
-    tar -xzvf bitcoin-$BITCOINVERSION-x86_64-linux-gnu.tar.gz
-    export PATH=$PATH:$(pwd)/bitcoin-$BITCOINVERSION/bin
-    cd integration_test
-    ./run.sh
-    exit 0
-else
-  # Regular build/unit test.
-  cargo build --verbose
-  cargo test --verbose
-  cargo build --verbose --examples
-fi
diff --git a/json/Cargo.toml b/json/Cargo.toml
index 8f3d67cc..63a85a56 100644
--- a/json/Cargo.toml
+++ b/json/Cargo.toml
@@ -20,7 +20,7 @@ name = "bitcoincore_rpc_json"
 path = "src/lib.rs"
 
 [dependencies]
-serde = { version = "1", features = [ "derive" ] }
-serde_json = "1"
+serde = { version = "1.0.156", features = [ "derive" ] }
+serde_json = "1.0.96"
 
 bitcoin = { version = "0.31.0", features = ["serde", "rand-std"]}