diff --git a/docs/requirements.txt b/docs/requirements.txt
index c03e3327f4..acc983129f 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -4,15 +4,13 @@ pytorch-ignite==0.4.4
 numpy>=1.17
 itk>=5.0, <=5.1.2
 nibabel
-cucim==0.18.2
-openslide-python==1.1.2
 parameterized
 scikit-image>=0.14.2
 tensorboard
 commonmark==0.9.1
 recommonmark==0.6.0
-Sphinx==3.3.0
-sphinx-rtd-theme==0.5.0
+Sphinx==3.5.3
+sphinx-rtd-theme==0.5.2
 sphinxcontrib-applehelp
 sphinxcontrib-devhelp
 sphinxcontrib-htmlhelp