diff --git a/docs/release_notes.md b/docs/release_notes.md
index 03d0329..55d7ae3 100644
--- a/docs/release_notes.md
+++ b/docs/release_notes.md
@@ -8,7 +8,7 @@
 
 ### Minor Changes and Bug Fixes
 
-*
+* Keep `pymdown-extensions` below 12 under Python 3.10, the Python of the documentation build, where `mkdocstrings` stops at 1.0.6, which fails with it (`Highlight.__init__() missing 1 required positional argument: 'md'`). See [PR #127](https://github.com/SPSUnipi/pySMSpp/pull/127)
 
 
 ## Version v0.0.14
diff --git a/pyproject.toml b/pyproject.toml
index 495a5fd..a64a7f0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,6 +53,8 @@ docs=[
     "mkdocs-jupyter>=0.24",
     "mkdocs-autorefs>=0.5",
     "pymdown-extensions>=10.0",
+    # mkdocstrings 1.0.6, the last one for Python 3.10, fails with 12.0
+    "pymdown-extensions<12; python_version < '3.11'",
     "scikit-learn",
     "libsvm-official",
 ]