diff --git a/TODO b/TODO
index 0ec57ac..d3c2515 100644
--- a/TODO
+++ b/TODO
@@ -4,7 +4,13 @@ General
  * QPDF::checkLinearization writes things to std::cout, which makes it
    hard for GUIs that want to display the result.  Go through all
    library code and get rid of use of std::cout and std::cerr,
-   replacing them with some better mechanism.
+   replacing them with some better mechanism.  To avoid changing the
+   ABI, add two new methods: one that takes a std::ostream& and one
+   that takes a reference to a std::vector<std::string>.  The real
+   code should append to the vector.  The ostream version should
+   remember to catch exceptions, output the vector elements, and
+   rethrow if needed.  The old version should call the ostream version
+   with std::cout.
 
  * In general, take a fresh look at private methods to see which, if
    any, should be protected.