diff --git a/Changelog.md b/Changelog.md
index 92670e6d79d420411f983a081aa57992531c7ab9..92cd78207f61a0dd435a137f5a7525476f6d67f9 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,5 @@
+We are using here tghe same convention as Ubuntu: a release is typically named vYY.MM, where YY is the last two digits of current year and MM two digits representing the month.
+
 # [v21.05](https://gitlab.inria.fr/formations/cpp/gettingstartedwithmoderncpp/-/releases/v21.05)
 
 A third training session is given in [May 2021](https://sed.saclay.inria.fr/formations/2021-05-17-cpp/), under a slightly different format due to Covid 19 crisis: 5 half days in visio and no TP during the sessions.