diff --git a/requirements.txt b/requirements.txt
index 2053e92..57a2bbc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,18 +1,8 @@
-Sphinx~=2.4.4
-actdiag~=2.0.0
-blockdiag~=1.5.4
-doc8~=0.8.0
+Sphinx~=4.1.2
+doc8~=0.9.0
 docutils==0.16
-nwdiag~=2.0.0
 recommonmark~=0.6.0
-seqdiag~=2.0.0
-sphinx-rtd-theme~=0.4.3
-sphinxcontrib-actdiag~=2.0.0
-sphinxcontrib-blockdiag~=2.0.0
-sphinxcontrib-nwdiag~=2.0.0
+sphinx-rtd-theme~=0.5.2
 sphinxcontrib-openapi~=0.6.0
-sphinxcontrib-seqdiag~=2.0.0
-sphinxcontrib-spelling~=4.3.0
+sphinxcontrib-spelling~=7.2.1
 git+https://github.com/zdw/sphinx-multiversion@ec7c01cdaf2f9241245e84483dfb9bc0d0dffc62
-# sphinx-autoapi~=1.2.1
-# sphinxcontrib-golangdomain==0.2.0.dev0