diff --git a/.github/workflows/checks-and-builds.yaml b/.github/workflows/checks-and-builds.yaml
index 45523fc..45bc1de 100644
--- a/.github/workflows/checks-and-builds.yaml
+++ b/.github/workflows/checks-and-builds.yaml
@@ -24,7 +24,7 @@ jobs:
     needs: check-style
     runs-on: ubuntu-latest
     container:
-      image: rapidsai/ci-conda:latest
+      image: rapidsai/ci-conda:cuda12.2.2-ubuntu22.04-py3.9
     env:
       PUBLISH: "${{ inputs.publish }}"
     steps:
@@ -42,7 +42,7 @@ jobs:
     needs: check-style
     runs-on: ubuntu-latest
     container:
-      image: rapidsai/ci-wheel:latest
+      image: rapidsai/ci-wheel:cuda12.2.2-ubuntu20.04-py3.9
     env:
       PUBLISH: "${{ inputs.publish }}"
       RAPIDS_CONDA_TOKEN: ${{ secrets.CONDA_RAPIDSAI_WHEELS_NIGHTLY_TOKEN }}
diff --git a/rapids_build_backend/config.py b/rapids_build_backend/config.py
index 66f82c7..3e67d26 100644
--- a/rapids_build_backend/config.py
+++ b/rapids_build_backend/config.py
@@ -6,16 +6,18 @@
 from .utils import _get_pyproject
 
 if TYPE_CHECKING:
-    from typing import Callable
+    from typing import Callable, Union
 
     # config options can be one of these types...
-    config_val_type = str | bool | None
+    config_val_type = Union[str, bool, None]
 
     # ... or a callable that returns one of those or some other mutable types
     mutable_config_val_type = list[str]
-    config_val_callable = Callable[[], config_val_type | mutable_config_val_type]
+    config_val_callable = Callable[[], Union[config_val_type, mutable_config_val_type]]
 
-    config_options_type = dict[str, tuple[config_val_type | config_val_callable, bool]]
+    config_options_type = dict[
+        str, tuple[Union[config_val_type, config_val_callable], bool]
+    ]
 
 
 class Config:
diff --git a/rapids_build_backend/impls.py b/rapids_build_backend/impls.py
index c15bc28..d4d8450 100644
--- a/rapids_build_backend/impls.py
+++ b/rapids_build_backend/impls.py
@@ -7,6 +7,7 @@
 from contextlib import contextmanager
 from functools import lru_cache
 from importlib import import_module
+from typing import Union
 
 import rapids_dependency_file_generator
 import tomli_w
@@ -99,7 +100,7 @@ def _get_cuda_suffix(require_cuda=False) -> str:
 
 
 @lru_cache
-def _get_git_commit() -> str | None:
+def _get_git_commit() -> Union[str, None]:
     """Get the current git commit.
 
     Returns None if git is not in the PATH or if it fails to find the commit.