Document non-working versions of Active-HDL
@@ -164,6 +164,14 @@ In order to use this simulator, set :make:var:`SIM` to ``activehdl``:
make SIM=activehdl
+.. warning::
+
+ cocotb does not work with some versions of Active-HDL (see :issue:`1494`).
+
+ Known affected versions:
+
+ - Aldec Active-HDL 10.4a
+ - Aldec Active-HDL 10.5a
.. _sim-questa:
