1 files changed, 5 insertions, 1 deletions
diff --git a/TODOs.md b/TODOs.md
index 91a4674..3bfd318 100644
--- a/TODOs.md
+++ b/TODOs.md
@@ -27,7 +27,11 @@ Current candidates are:
 ## TODO Make `test_really_long_list` runnable {#task-c1129666-b373-4b9d-8e10-927689048b05}
 - TODO in 2021-01-31
 
-## TODO Improve speed even further {#task-05c7f068-e935-457f-89ea-1f38227e7779}
+## CANCELLED Improve speed even further {#task-05c7f068-e935-457f-89ea-1f38227e7779}
+- CANCELLED in 2021-03-06
+
+  [#task-c1129666-b373-4b9d-8e10-927689048b05](#task-c1129666-b373-4b9d-8e10-927689048b05) supersedes this.
+  And even better: it has runnable code that can be executed for verifying the performance improvement.
 - TODO in 2021-01-29
 
 ---