diff --git a/core/init/__init__.py.in b/core/init/__init__.py.in
index 47141c5c6977ca433678d4233b67aaeeece4328b..d99f55566d72363ee2375bc2e23e360e2472f98c 100644
--- a/core/init/__init__.py.in
+++ b/core/init/__init__.py.in
@@ -28,6 +28,9 @@ import ost
 from ost import conop
 from ost import io
 
+# It is no longer needed to set the default compound lib with OST >= 2.5.
+# This function is kept as is for backward compatibility with earlier OST
+# versions. Consider updating in a future release.
 def SetCompoundsChemlib(path_to_chemlib=@OST_COMPOUNDS_CHEMLIB_PATH@):
     """SetCompoundsChemlib(path_to_chemlib)
     Load a compounds library. Does not return anything, the library is just