diff --git a/docs/conf.py b/docs/conf.py
index 89f9045c..759f2a09 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -172,7 +172,7 @@
 
 
 def linkcode_resolve(
-    domain: str, info: dict[str, str]
+    domain: str, info: t.Dict[str, str]
 ) -> t.Union[None, str]:  # NOQA: C901
     """
     Determine the URL corresponding to Python object
diff --git a/src/unihan_db/bootstrap.py b/src/unihan_db/bootstrap.py
index d3382301..0f81026b 100644
--- a/src/unihan_db/bootstrap.py
+++ b/src/unihan_db/bootstrap.py
@@ -147,7 +147,7 @@ def is_bootstrapped(metadata: sqlalchemy.MetaData) -> bool:
 
 
 def bootstrap_data(
-    options: UntypedUnihanData | None = None,
+    options: t.Union[UntypedUnihanData, None] = None,
 ) -> t.Optional["UntypedNormalizedData"]:
     if options is None:
         options = {}