diff --git a/src/nodenorm/babel.py b/src/nodenorm/babel.py
new file mode 100644
index 0000000..3e30f22
--- /dev/null
+++ b/src/nodenorm/babel.py
@@ -0,0 +1,21 @@
+from urllib.parse import urlparse
+
+BABEL_RELEASES_URL = "https://github.com/NCATSTranslator/Babel/blob/main/releases"
+
+
+def get_babel_version(index_mapping: dict) -> str:
+    """Return the explicit Babel source version, with legacy URL fallback."""
+
+    source_metadata = index_mapping["mappings"]["_meta"]["src"]["nodenorm"]
+    if babel_version := source_metadata.get("version"):
+        return babel_version
+
+    compendia_url = source_metadata["url"]
+    parsed_compendia_url = urlparse(compendia_url)
+    return parsed_compendia_url.path.rstrip("/").rsplit("/", maxsplit=1)[-1]
+
+
+def get_babel_release_url(version: str) -> str:
+    """Return the canonical Babel release-notes URL for a build version."""
+
+    return f"{BABEL_RELEASES_URL}/{version}/README.md"
diff --git a/src/nodenorm/biolink.py b/src/nodenorm/biolink.py
index fd0be9f..d6e92ad 100644
--- a/src/nodenorm/biolink.py
+++ b/src/nodenorm/biolink.py
@@ -8,7 +8,7 @@
 # > get_normalized_nodes
 # > get_semantic_types
 
-DEFAULT_BIOLINK_MODEL_VERSION = "v4.2.6-rc5"
+DEFAULT_BIOLINK_MODEL_VERSION = "v4.3.3"
 BIOLINK_MODEL_VERSION = os.getenv("BIOLINK_VERSION", DEFAULT_BIOLINK_MODEL_VERSION)
 BIOLINK_MODEL_URL = (
     f"https://raw.githubusercontent.com/biolink/biolink-model/{BIOLINK_MODEL_VERSION}/biolink-model.yaml"
diff --git a/src/nodenorm/handlers/health.py b/src/nodenorm/handlers/health.py
index 19f986a..2dcd5e5 100644
--- a/src/nodenorm/handlers/health.py
+++ b/src/nodenorm/handlers/health.py
@@ -1,11 +1,11 @@
 import importlib.resources
 import json
 from functools import lru_cache
-from urllib.parse import urlparse
 
 from elasticsearch import AsyncElasticsearch
 
 import nodenorm
+from nodenorm.babel import get_babel_release_url, get_babel_version
 from nodenorm.biolink import BIOLINK_MODEL_VERSION
 from nodenorm.handlers.base import NodeNormalizationBaseHandler
 
@@ -32,10 +32,8 @@ async def get(self):
 
         mapping_response = await async_client.indices.get_mapping(index=search_indices)
         index_mapping = next(iter(mapping_response.values()))
-        compendia_url = index_mapping["mappings"]["_meta"]["src"]["nodenorm"]["url"]
-        parsed_compendia_url = urlparse(compendia_url)
-        babel_version = parsed_compendia_url.path.rstrip("/").rsplit("/", maxsplit=1)[-1]
-        babel_markdown = f"https://github.com/ncatstranslator/Babel/blob/master/releases/{babel_version}.md"
+        babel_version = get_babel_version(index_mapping)
+        babel_version_url = get_babel_release_url(babel_version)
         version = get_openapi_version()
         try:
             attributes = [
@@ -61,7 +59,7 @@ async def get(self):
                 "status": "error",
                 "version": version,
                 "babel_version": babel_version,
-                "babel_version_url": babel_markdown,
+                "babel_version_url": babel_version_url,
                 "backend": "elasticsearch",
             }
         else:
@@ -69,7 +67,7 @@ async def get(self):
                 "status": "running",
                 "version": version,
                 "babel_version": babel_version,
-                "babel_version_url": babel_markdown,
+                "babel_version_url": babel_version_url,
                 "backend": "elasticsearch",
                 "biolink_model_toolkit_version": BIOLINK_MODEL_VERSION,
                 **nodes,
diff --git a/tests/test_health.py b/tests/test_health.py
new file mode 100644
index 0000000..14b536d
--- /dev/null
+++ b/tests/test_health.py
@@ -0,0 +1,44 @@
+from nodenorm.babel import get_babel_release_url, get_babel_version
+
+
+def index_mapping(source_metadata):
+    return {
+        "mappings": {
+            "_meta": {
+                "src": {
+                    "nodenorm": source_metadata,
+                }
+            }
+        }
+    }
+
+
+def test_babel_version_uses_explicit_source_version():
+    mapping = index_mapping(
+        {
+            "version": "2026jul22",
+            "url": "https://stars.renci.org/var/babel_outputs/latest/VERSION.txt",
+        }
+    )
+
+    babel_version = get_babel_version(mapping)
+
+    assert babel_version == "2026jul22"
+    assert get_babel_release_url(babel_version) == (
+        "https://github.com/NCATSTranslator/Babel/blob/main/releases/2026jul22/README.md"
+    )
+
+
+def test_babel_version_falls_back_to_legacy_source_url():
+    mapping = index_mapping(
+        {
+            "url": "https://stars.renci.org/var/babel_outputs/2025sep1/",
+        }
+    )
+
+    babel_version = get_babel_version(mapping)
+
+    assert babel_version == "2025sep1"
+    assert get_babel_release_url(babel_version) == (
+        "https://github.com/NCATSTranslator/Babel/blob/main/releases/2025sep1/README.md"
+    )