diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index dab5ea7..d8e385a 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -40,8 +40,8 @@ jobs:
     strategy:
       matrix:
         rust:
-          - version: stable # STABLE
-            features: miniscript
+#          - version: stable # STABLE
+#            features: miniscript
           - version: 1.63.0 # MSRV
             features: miniscript
         emulator:
@@ -58,17 +58,8 @@ jobs:
             ~/.cargo/git
             target
           key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.toml','**/Cargo.lock') }}
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v2
-      - name: Build and push
-        uses: docker/build-push-action@v3
-        with:
-          context: ci/
-          file: ci/Dockerfile.${{ matrix.emulator.name }}
-          tags: hwi/${{ matrix.emulator.name }}_emulator:latest
-          load: true
-          cache-from: type=gha
-          cache-to: type=gha
+      - name: Build simulator image
+        run: docker build -t hwi/${{ matrix.emulator.name }}_emulator:latest ./ci -f ci/Dockerfile.${{ matrix.emulator.name }}
       - name: Run simulator image
         run: docker run --name simulator --network=host hwi/${{ matrix.emulator.name }}_emulator &
       - name: Install Python
diff --git a/ci/Dockerfile.ledger b/ci/Dockerfile.ledger
index b593664..5c76716 100644
--- a/ci/Dockerfile.ledger
+++ b/ci/Dockerfile.ledger
@@ -1,4 +1,4 @@
-FROM ghcr.io/ledgerhq/speculos
+FROM ghcr.io/ledgerhq/speculos:sha-f430e51
 
 RUN apt-get update
 RUN apt-get install wget -y
diff --git a/clippy.toml b/clippy.toml
index 516ad1f..69478ce 100644
--- a/clippy.toml
+++ b/clippy.toml
@@ -1 +1 @@
-msrv="1.48.0"
+msrv="1.63.0"
diff --git a/src/lib.rs b/src/lib.rs
index fa47492..69c00cc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -59,7 +59,7 @@ mod tests {
     #[serial]
     fn test_enumerate() {
         let devices = HWIClient::enumerate().unwrap();
-        assert!(devices.len() > 0);
+        assert!(!devices.is_empty());
     }
 
     #[test]
@@ -83,7 +83,7 @@ mod tests {
             .expect("No devices found. Either plug in a hardware wallet, or start a simulator.")
             .as_ref()
             .expect("Error when opening the first device");
-        HWIClient::get_client(&device, true, TESTNET).unwrap()
+        HWIClient::get_client(device, true, TESTNET).unwrap()
     }
 
     #[test]
@@ -119,8 +119,8 @@ mod tests {
         let client = get_first_device();
         let account = Some(10);
         let descriptor = client.get_descriptors::<String>(account).unwrap();
-        assert!(descriptor.internal.len() > 0);
-        assert!(descriptor.receive.len() > 0);
+        assert!(!descriptor.internal.is_empty());
+        assert!(!descriptor.receive.is_empty());
     }
 
     #[test]
@@ -141,8 +141,8 @@ mod tests {
         let descriptor = client
             .get_descriptors::<Descriptor<DescriptorPublicKey>>(account)
             .unwrap();
-        assert!(descriptor.internal.len() > 0);
-        assert!(descriptor.receive.len() > 0);
+        assert!(!descriptor.internal.is_empty());
+        assert!(!descriptor.receive.is_empty());
     }
 
     #[test]
@@ -199,7 +199,7 @@ mod tests {
     fn test_sign_tx() {
         let devices = HWIClient::enumerate().unwrap();
         let device = devices.first().unwrap().as_ref().unwrap();
-        let client = HWIClient::get_client(&device, true, TESTNET).unwrap();
+        let client = HWIClient::get_client(device, true, TESTNET).unwrap();
         let derivation_path = DerivationPath::from_str("m/44'/1'/0'/0/0").unwrap();
 
         let address = client
@@ -237,7 +237,7 @@ mod tests {
                 input: vec![previous_txin],
                 output: vec![TxOut {
                     value: Amount::from_sat(50),
-                    script_pubkey: script_pubkey,
+                    script_pubkey,
                 }],
             },
             xpub: Default::default(),