diff --git a/docs/conf.py b/docs/conf.py
index 93c8130..a423956 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -70,7 +70,7 @@
 # Some change in dependencies made us need to replace `var` with
 # `env.config.html_context['var']`.
 nbsphinx_prolog = r"""
-{% set docname = 'docs/' + env.doc2path(env.docname, base=None) %}
+{% set docname = 'docs' / env.doc2path(env.docname, base=None) %}
 {% set git_ref = 'main' if not env.config.html_context['READTHEDOCS'] else
                  env.config.html_context['github_version']
                  if '.' not in env.config.html_context['current_version'] else
diff --git a/docs/requirements.txt b/docs/requirements.txt
index 4f92a8a..aa612a8 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,4 +1,4 @@
 sphinx_rtd_theme>=0.5.0
 ipython
 sphinxcontrib-bibtex>=2.3.0
-nbsphinx==0.8.12
+nbsphinx