diff --git a/docs/changelog.rst b/docs/changelog.rst
index 6e19ac7..af918be 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -1,6 +1,11 @@
 Changelog
 =========
 
+0.6.7 (2024-12-15)
+------------------
+
+-  :meth:`~ocdsextensionregistry.versioned_release_schema.get_versioned_release_schema`: Copy schema before modifying in-place.
+
 0.6.6 (2024-12-15)
 ------------------
 
diff --git a/docs/conf.py b/docs/conf.py
index ed91d04..7c39a8f 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -23,7 +23,7 @@
 author = "Open Contracting Partnership"
 
 # The short X.Y version
-version = "0.6.6"
+version = "0.6.7"
 # The full version, including alpha/beta/rc tags
 release = version
 
diff --git a/ocdsextensionregistry/versioned_release_schema.py b/ocdsextensionregistry/versioned_release_schema.py
index 59585e4..004360d 100644
--- a/ocdsextensionregistry/versioned_release_schema.py
+++ b/ocdsextensionregistry/versioned_release_schema.py
@@ -255,6 +255,8 @@ def _remove_metadata_and_extended_keywords(schema):
 
 def get_versioned_release_schema(schema, tag):
     """Return the versioned release schema."""
+    schema = deepcopy(schema)
+
     # Update schema metadata.
     schema["id"] = (
         f"https://standard.open-contracting.org/schema/{tag}/versioned-release-validation-schema.json"
diff --git a/pyproject.toml b/pyproject.toml
index a068a8e..8335d85 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "ocdsextensionregistry"
-version = "0.6.6"
+version = "0.6.7"
 authors = [{name = "Open Contracting Partnership", email = "data@open-contracting.org"}]
 description = "Eases access to information from the extension registry of the Open Contracting Data Standard"
 readme = "README.rst"