diff --git a/docs/environment.yml b/docs/environment.yml
index 81c72d7..d6a9e3b 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -5,3 +5,4 @@ channels:
 
 dependencies:
   - breathe
+  - sphinx_rtd_theme
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 6e1dd54..3243e39 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -20,7 +20,7 @@ def setup(app):
     app.add_css_file("main_stylesheet.css")
 
 
-extensions = ["breathe"]
+extensions = ["breathe", "sphinx_rtd_theme"]
 breathe_projects = {"xeus-octave": "../xml"}
 templates_path = ["_templates"]
 html_static_path = ["_static"]
diff --git a/readthedocs.yml b/readthedocs.yml
index 004a03a..38f414b 100644
--- a/readthedocs.yml
+++ b/readthedocs.yml
@@ -1,2 +1,9 @@
+version: 2
+
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "mambaforge-22.9"
+
 conda:
-  file: docs/environment.yml
+  environment: docs/environment.yml