diff --git a/ci/rtd-requirements.txt b/ci/rtd-requirements.txt
index 4f07be4ab8..ca4bb52c17 100644
--- a/ci/rtd-requirements.txt
+++ b/ci/rtd-requirements.txt
@@ -1,5 +1,4 @@
 # RTD is currently installing 1.5.3, which has a bug in :lineno-match:
-# 1.7.0 hits https://github.com/sphinx-doc/sphinx/issues/4609
-sphinx == 1.6.7
+sphinx >= 1.7.0
 sphinx_rtd_theme
 sphinxcontrib-trio
diff --git a/docs/source/conf.py b/docs/source/conf.py
index fbb05d7ed0..3ca448ae8b 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -28,11 +28,13 @@
 nitpicky = True
 # Except for these ones, which we expect to point to unknown targets:
 nitpick_ignore = [
-    ("py:obj", "CapacityLimiter-like object"),
-    ("py:obj", "bytes-like"),
+    ("py:class", "CapacityLimiter-like object"),
+    ("py:class", "bytes-like"),
+    ("py:class", "None"),
     # trio.abc is documented at random places scattered throughout the docs
     ("py:mod", "trio.abc"),
 ]
+autodoc_inherit_docstrings = False
 
 # XX hack the RTD theme until
 #   https://github.com/rtfd/sphinx_rtd_theme/pull/382