diff --git a/docs/conf.py b/docs/conf.py
index 73242edb0..a770adaff 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -75,8 +75,6 @@ def _load_data(self, env, data_source, encoding):
     'videos/prague/2018/tackling-technical-debt-in-the-docs-louise-fahey.rst',
 ]
 
-html4_writer = True
-
 # We use these *local* environment variables for private info like free ticket links
 
 cfp_variables = {}