diff --git a/doc/utils/requirements.txt b/doc/utils/requirements.txt
index f367727d20..9b8e106875 100644
--- a/doc/utils/requirements.txt
+++ b/doc/utils/requirements.txt
@@ -1,7 +1,7 @@
-Sphinx==4.0.3
-sphinxcontrib-spelling==7.2.1
+Sphinx
+sphinxcontrib-spelling
 git+git://github.com/akohlmey/sphinx-fortran@parallel-read
-sphinx_tabs==3.2.0
-breathe==4.31.0
-Pygments==2.10.0
-six==1.16.0
+sphinx_tabs
+breathe
+Pygments
+six