diff --git a/HISTORY.md b/HISTORY.md
index 48ea5db..11229b1 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,6 +1,14 @@
 History of SixtyPical
 =====================
 
+0.21-2023.0309
+--------------
+
+*   Python 3 is the default interpreter for `sixtypical`.
+*   Test appliance added for testing under Python 2.7.
+*   `dcc6502` test adapter made runnable under both
+    Python 2 and Python 3.
+
 0.21
 ----