diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 71be36f..f5dab19 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -22,7 +22,7 @@ jobs:
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v7
         with:
           python-version: ${{ matrix.python-version }}
       - name: Cache pip dependencies
@@ -71,7 +71,7 @@ jobs:
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
       - name: Set up Python 3.11
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v7
         with:
           python-version: "3.11"
       - name: Cache pip dependencies
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 085b9a8..0401022 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -22,7 +22,7 @@ jobs:
           fetch-depth: 0
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@v7
         with:
           python-version: "3.11"
 
@@ -36,7 +36,7 @@ jobs:
         uses: pypa/gh-action-pypi-publish@release/v1
 
       - name: Create GitHub Release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@v3
         with:
           files: dist/*
           generate_release_notes: true
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 0169e0c..32bb9c9 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -67,12 +67,6 @@ python -m build
 
 The artifacts will be generated in the `dist/` directory.
 
-Since this is a Python project using `setuptools_scm`, versioning is handled automatically based on git tags. I've adapted the workflow from your JS library to Python conventions while maintaining the same straightforward structure.
-
-Add this section to the end of your `CONTRIBUTING.md`:
-
----
-
 ## Releases
 
 Releases are automated via GitHub Actions and triggered by pushing git tags. The project uses `setuptools_scm`, so the version is derived directly from the tag name.
diff --git a/docs/results.md b/docs/results.md
index c4eb0fd..ddf87ac 100644
--- a/docs/results.md
+++ b/docs/results.md
@@ -14,7 +14,7 @@ hr = results[0]['vitals']['heart_rate']['value']
 
 Waveform data, confidences and timestamps are returned as lists; scalar values are Python floats.
 
-Besides `face`, `vitals`, `waveforms` and `message`, each result contains:
+Besides `face`, `vitals`, `waveforms`, `message`, `model_used` (VitalLens API only) and `core_version`, each result contains:
 
 | Key | Contents |
 | --- | --- |
diff --git a/pyproject.toml b/pyproject.toml
index aed82c1..2403932 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,7 +29,7 @@ dependencies = [
     "python-dotenv>=1.0",
     "pyyaml>=6.0.1",
     "requests>=2.32.0",
-    "vitallens-core==0.4.0",
+    "vitallens-core==0.4.2",
 ]
 dynamic = ["version"]
 
diff --git a/tests/test_client.py b/tests/test_client.py
index 84ba756..bf10a69 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -8,6 +8,7 @@
 import sys
 sys.path.append('../vitallens-python')
 
+import vitallens_core
 from vitallens.client import VitalLens, Method
 
 @pytest.mark.parametrize("method_arg", [Method.G, "chrom", "pos"])
@@ -30,6 +31,8 @@ def test_VitalLens(request, method_arg, detect_faces, file, export):
   assert np.asarray(result[0]['waveforms']['ppg_waveform']['confidence']).shape == (630,)
   np.testing.assert_allclose(result[0]['vitals']['heart_rate']['value'], 60, atol=10)
   assert result[0]['vitals']['heart_rate']['confidence'] == 1.0
+  assert result[0]['core_version'] == vitallens_core.core_version()
+  assert 'model_used' not in result[0]
   if export:
     test_json_path = os.path.join("test.json")
     assert os.path.exists(test_json_path)
@@ -62,14 +65,15 @@ def test_VitalLens_API(request):
   assert np.asarray(result[0]['waveforms']['respiratory_waveform']['confidence']).shape == (630,)
   assert 'hrv_sdnn' in result[0]['vitals']
   assert 'hrv_rmssd' in result[0]['vitals']
-  np.testing.assert_allclose(result[0]['vitals']['heart_rate']['value'], 60, atol=0.5)
+  # HR and HRV reference values from the contact PPG in examples/sample_vitals_2.csv
+  np.testing.assert_allclose(result[0]['vitals']['heart_rate']['value'], 60.4, atol=0.5)
   np.testing.assert_allclose(result[0]['vitals']['heart_rate']['confidence'], 1.0, atol=0.1)
   np.testing.assert_allclose(result[0]['vitals']['respiratory_rate']['value'], 13, atol=1.0)
   np.testing.assert_allclose(result[0]['vitals']['respiratory_rate']['confidence'], 1.0, atol=0.1)
   supports_hrv = result[0].get('model_used', '') == 'vitallens-2.0'
   if supports_hrv:
-    np.testing.assert_allclose(result[0]['vitals']['hrv_sdnn']['value'], 40, atol=20)
-    np.testing.assert_allclose(result[0]['vitals']['hrv_rmssd']['value'], 30, atol=20)
+    np.testing.assert_allclose(result[0]['vitals']['hrv_sdnn']['value'], 62, atol=10)
+    np.testing.assert_allclose(result[0]['vitals']['hrv_rmssd']['value'], 54, atol=10)
   assert not os.path.exists("test.json")
 
 @pytest.mark.integration
diff --git a/tests/test_stream.py b/tests/test_stream.py
index d3cc8b9..f7750e1 100644
--- a/tests/test_stream.py
+++ b/tests/test_stream.py
@@ -74,4 +74,5 @@ def test_stream_session():
     assert len(res) > 0
     assert 'vitals' in res[0]
     assert 'waveforms' in res[0]
-    assert 'ppg_waveform' in res[0]['waveforms']
\ No newline at end of file
+    assert 'ppg_waveform' in res[0]['waveforms']
+    assert res[0]['core_version'] == vc.core_version()
\ No newline at end of file
diff --git a/tests/test_vitallens.py b/tests/test_vitallens.py
index bd07b7d..93be4c9 100644
--- a/tests/test_vitallens.py
+++ b/tests/test_vitallens.py
@@ -152,6 +152,7 @@ def test_VitalLensRPPGMethod_file_mock(mock_post, mock_resolve_config, request,
   assert data['respiratory_waveform'].shape == (test_video_ndarray.shape[0],)
   assert conf['respiratory_waveform'].shape == (test_video_ndarray.shape[0],)
   assert live.shape == (test_video_ndarray.shape[0],)
+  assert method.model_used == requested_model
 
 @pytest.mark.parametrize("override_fps_target", [None, 15, 10])
 @pytest.mark.parametrize("long", [True])
diff --git a/vitallens/client.py b/vitallens/client.py
index 94ca557..a1cc191 100644
--- a/vitallens/client.py
+++ b/vitallens/client.py
@@ -167,7 +167,9 @@ def __call__(
               },
               <other waveforms...>
             },
-            'message': <Message about estimates>
+            'message': <Message about estimates>,
+            'model_used': 'vitallens-2.0',
+            'core_version': '0.4.2'
           },
           { 
             <same structure for face 2 if present>
@@ -234,6 +236,8 @@ def __call__(
             for k, v in session_result.rolling_vitals.items()
         } if session_result.rolling_vitals else {},
         'message': session_result.message,
+        **({'model_used': self.rppg.model_used} if getattr(self.rppg, 'model_used', None) else {}),
+        'core_version': vc.core_version(),
         'fps': session_result.fps,
         'n': len(session_result.timestamp),
         'time': session_result.timestamp
@@ -271,7 +275,7 @@ def stream(self, on_result: Callable = None) -> StreamSession:
     Returns:
       session: A `StreamSession` context manager. The session object provides:
         * `push(frame, timestamp, face=None)`: Ingests a new RGB frame. 
-          `timestamp` should be in seconds (e.g., `time.time()`).
+          `timestamp` is the capture time in seconds (e.g., `time.monotonic()`).
         * `get_result(block=False, timeout=None)`: Pulls the latest analysis 
           results from the queue.
         * `current_face`: The most recently detected face coordinates.
diff --git a/vitallens/methods/vitallens.py b/vitallens/methods/vitallens.py
index 275b8fc..d4f2424 100644
--- a/vitallens/methods/vitallens.py
+++ b/vitallens/methods/vitallens.py
@@ -115,6 +115,7 @@ def __init__(
     self.session_config = _resolve_model_config(api_key=api_key, model_name=requested_model_name, proxies=proxies)
     self.parse_config(self.session_config)
     self.resolved_model = self.session_config.model_name
+    self.model_used = None
     self.requested_model_name = requested_model_name if requested_model_name != "vitallens" else None
     self.http_session = requests.Session()
 
@@ -270,6 +271,7 @@ def infer_stream(self, frames: np.ndarray, fps: float, state=None):
       else: raise VitalLensAPIError(f"API Error: {response_body.get('message')}")
 
     response_body = response.json()
+    self.model_used = response_body.get('model_used', self.model_used)
 
     api_waveforms = response_body.get("waveforms", {})
     sig_dict, conf_dict = {}, {}
@@ -378,6 +380,7 @@ def process_api_batch(
         raise VitalLensAPIError(f"API Error: {response_body['message']}")
       else:
         raise Exception(f"Error {response.status_code}: {response_body['message']}")
+    self.model_used = response_body.get('model_used', self.model_used)
     # Dynamic dict parsing
     api_waveforms = response_body.get("waveforms", {})
     sig_ds = {}
diff --git a/vitallens/stream.py b/vitallens/stream.py
index 1ad1d0a..439d5c5 100644
--- a/vitallens/stream.py
+++ b/vitallens/stream.py
@@ -399,6 +399,8 @@ def _format_result(self, session_result):
       'vitals': {},
       'waveforms': {},
       'message': session_result.message,
+      **({'model_used': self.rppg.model_used} if getattr(self.rppg, 'model_used', None) else {}),
+      'core_version': vc.core_version(),
       'fps': session_result.fps,
       'n': len(session_result.timestamp),
       'time': session_result.timestamp