diff --git a/include/armadillo_bits/fn_sort_index.hpp b/include/armadillo_bits/fn_sort_index.hpp
index 7b844803..8d53effe 100644
--- a/include/armadillo_bits/fn_sort_index.hpp
+++ b/include/armadillo_bits/fn_sort_index.hpp
@@ -67,7 +67,7 @@ sort_index
 
 
 
-// TODO: deprecate this function in lieu of sort_index()
+// DO NOT USE: kept only for compatibility with old user code
 template<typename T1>
 arma_warn_unused
 arma_inline
@@ -84,7 +84,7 @@ stable_sort_index
 
 
 
-// TODO: deprecate this function in lieu of sort_index()
+// DO NOT USE: kept only for compatibility with old user code
 template<typename T1, typename T2>
 arma_warn_unused
 inline