diff --git a/TODO b/TODO
index cf0dcd7a..1f1a7cfc 100644
--- a/TODO
+++ b/TODO
@@ -1,3 +1,10 @@
+- the gif tests in the suite sometimes fail with giflib5 because of an
+  uninitialized struct in giflib, see
+
+	https://sourceforge.net/p/giflib/bugs/94/
+
+  sadly ubuntu 16.04 only comes with giflib5, and giflib5 is currently broken
+
 - I like the new int mask creator in reducev, can we use it in im_vips2imask()
   as well?