diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index a5454c3b..551b8c48 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -316,6 +316,8 @@ Upcoming Release
 
 * Mark downloaded files as ``ancient`` rather than ``protected``.
 
+* Fix file name enconding in optional rule :mod:`build_biomass_transport_costs` depending on the operating system.
+
 PyPSA-Eur 0.10.0 (19th February 2024)
 =====================================