diff --git a/README.md b/README.md
index 01ac5e1..8ec886e 100644
--- a/README.md
+++ b/README.md
@@ -2,4 +2,7 @@
 librairie de manipulation des données du Concervatoire d'Espaces Naturels de l'Isère.
 
 ## Install
-pip install git+https://framagit.org/cen-colas/pycen.git
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+pip install git+https://framagit.org/cen-colas/pycen.git
+
+## Upgrade
+pip install --upgrade git+https://framagit.org/cen-colas/pycen.git
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