diff --git a/docs/conf.py b/docs/conf.py
index af55f506d5..7768611e89 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -29,14 +29,15 @@
 import os
 import sys
 import sphinx
-from sphinx.errors import VersionRequirementError
+from sphinx.errors import ConfigError
 
 # Make Sphinx fail cleanly if using an old Python, rather than obscurely
 # failing because some code in one of our extensions doesn't work there.
-# Unfortunately this doesn't display very neatly (there's an unavoidable
-# Python backtrace) but at least the information gets printed...
+# In newer versions of Sphinx this will display nicely; in older versions
+# Sphinx will also produce a Python backtrace but at least the information
+# gets printed...
 if sys.version_info < (3,5):
-    raise VersionRequirementError(
+    raise ConfigError(
         "QEMU requires a Sphinx that uses Python 3.5 or better\n")
 
 # The per-manual conf.py will set qemu_docdir for a single-manual build;