diff --git a/environment.yml b/environment.yml
index fffb4b14..cc1b461d 100644
--- a/environment.yml
+++ b/environment.yml
@@ -7,14 +7,14 @@ dependencies:
   - msgpack-python
   - networkx
   - numpy
-  - openff-toolkit-base >=0.15.1
+#  - openff-toolkit-base >=0.15.1
   - openff-units >=0.3.1
   - openmm
   - pint
   - pip
   - pooch >= 1.9.0  # min needed for https://github.com/fatiando/pooch/issues/502
   - py3dmol  # opt
-  - pydantic >=2.0, <2.12
+  - pydantic ==2.13
   - pytest
   - pytest-cov
   - pytest-xdist
@@ -22,3 +22,6 @@ dependencies:
   - typing-extensions
   - ipywidgets  # opt
   - zstandard
+  - pip:
+      - git+https://github.com/openforcefield/openff-units@define-pydantic-schema
+      - git+https://github.com/openforcefield/openff-toolkit@main
diff --git a/gufe/vendor/openff/interchange/pydantic.py b/gufe/vendor/openff/interchange/pydantic.py
index 88853fd8..52d70f89 100644
--- a/gufe/vendor/openff/interchange/pydantic.py
+++ b/gufe/vendor/openff/interchange/pydantic.py
@@ -15,7 +15,7 @@ class _BaseModel(BaseModel):
     )
 
     def model_dump(self, **kwargs) -> dict[str, Any]:
-        return super().model_dump(serialize_as_any=True, **kwargs)
+        return super().model_dump(**kwargs)
 
     def model_dump_json(self, **kwargs) -> str:
-        return super().model_dump_json(serialize_as_any=True, **kwargs)
+        return super().model_dump_json(**kwargs)