diff --git a/sphinx_design/dropdown.py b/sphinx_design/dropdown.py
index 874d7e4..cebe956 100644
--- a/sphinx_design/dropdown.py
+++ b/sphinx_design/dropdown.py
@@ -142,7 +142,10 @@ class DropdownHtmlTransform(SphinxPostTransform):
 
     def run(self):
         """Run the transform"""
-        for node in self.document.traverse(lambda node: is_component(node, "dropdown")):
+        # Can just use "findall" once docutils 0.18.1+ is required
+        for node in getattr(self.document, "findall", self.document.traverse)(
+            lambda node: is_component(node, "dropdown")
+        ):
 
             # TODO option to not have card css (but requires more formatting)
             use_card = True
diff --git a/sphinx_design/tabs.py b/sphinx_design/tabs.py
index e874a43..090dd45 100644
--- a/sphinx_design/tabs.py
+++ b/sphinx_design/tabs.py
@@ -213,7 +213,9 @@ def get_unique_key(self):
 
     def run(self) -> None:
         """Run the transform."""
-        for tab_set in self.document.traverse(
+        # Can just use "findall" once docutils 0.18.1+ is required
+        meth = "findall" if hasattr(self.document, "findall") else "traverse"
+        for tab_set in getattr(self.document, meth)(
             lambda node: is_component(node, "tab-set")
         ):
             tab_set_identity = self.get_unique_key()