diff --git a/pyproject.toml b/pyproject.toml
index 9cf17bb..950d81f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,7 +37,7 @@ pytest-cov = { optional = true, version = "*" }
 sphinx = { optional = true, version = "<7" }                         # see issue at https://github.com/readthedocs/readthedocs.org/issues/10279
 nbsphinx = { optional = true, version = "<=0.9.3" }
 sphinx-autodoc-typehints = { optional = true, version = "<=1.23.0" }
-sphinx_rtd_theme = { optional = true, version = "<=1.3.0" }
+sphinx_rtd_theme = { optional = true, version = "<=2.0.0" }
 readthedocs-sphinx-ext = { optional = true, version = "<=2.2.3" }
 recommonmark = { optional = true, version = "<=0.7.1" }