diff --git a/sphinx_needs/data.py b/sphinx_needs/data.py
index aa9448a4c..2f8b099da 100644
--- a/sphinx_needs/data.py
+++ b/sphinx_needs/data.py
@@ -32,6 +32,12 @@
 
 LOGGER = getLogger(__name__)
 
+ENV_DATA_VERSION: Final = 2
+"""Version of the data stored in the environment.
+
+See https://www.sphinx-doc.org/en/master/extdev/index.html#extension-metadata
+"""
+
 
 class NeedsPartType(TypedDict):
     """Data for a single need part."""
diff --git a/sphinx_needs/needs.py b/sphinx_needs/needs.py
index 34ce59131..f647079f1 100644
--- a/sphinx_needs/needs.py
+++ b/sphinx_needs/needs.py
@@ -22,7 +22,12 @@
     build_needumls_pumls,
 )
 from sphinx_needs.config import NEEDS_CONFIG, LinkOptionsType, NeedsSphinxConfig
-from sphinx_needs.data import NeedsCoreFields, SphinxNeedsData, merge_data
+from sphinx_needs.data import (
+    ENV_DATA_VERSION,
+    NeedsCoreFields,
+    SphinxNeedsData,
+    merge_data,
+)
 from sphinx_needs.defaults import (
     GRAPHVIZ_STYLE_DEFAULTS,
     LAYOUTS,
@@ -303,6 +308,7 @@ def setup(app: Sphinx) -> dict[str, Any]:
         "version": VERSION,
         "parallel_read_safe": True,
         "parallel_write_safe": True,
+        "env_version": ENV_DATA_VERSION,
     }