diff --git a/requirements.readthedocs.txt b/requirements.readthedocs.txt
index b9422ea..fc186db 100644
--- a/requirements.readthedocs.txt
+++ b/requirements.readthedocs.txt
@@ -13,6 +13,9 @@ pyckles
 spextra
 skycalc_ipy
 
-numpydoc
+sphinx>=4.3.0
+sphinx-rtd-theme>=0.5.1
+jupyter_sphinx==0.2.3
 sphinxcontrib-apidoc
-sphinx==2.4
+nbsphinx
+numpydoc
\ No newline at end of file