diff --git a/scripts/install b/scripts/install
index 5756cd7..00e3f52 100644
--- a/scripts/install
+++ b/scripts/install
@@ -99,9 +99,7 @@ mkdir -p $final_path
 
 pushd $final_path
 
-export PIPENV_VENV_IN_PROJECT="enabled"
-
-ynh_exec_warn_less pipenv install jupyterlab==$jupyterlab_version jupyterhub notebook jupyterhub-ldapauthenticator --three
+PIPENV_VENV_IN_PROJECT="enabled" PIPENV_SKIP_LOCK=true  ynh_exec_warn_less pipenv install jupyterlab==$jupyterlab_version jupyterhub notebook jupyterhub-ldapauthenticator --three
 
 popd
 
diff --git a/scripts/upgrade b/scripts/upgrade
index c2e1426..462f828 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -116,9 +116,7 @@ then
 
 	pushd $final_path
 
-	export PIPENV_VENV_IN_PROJECT="enabled"
-
-	ynh_exec_warn_less pipenv install jupyterlab==$jupyterlab_version jupyterhub notebook jupyterhub-ldapauthenticator --three
+	PIPENV_VENV_IN_PROJECT="enabled" PIPENV_SKIP_LOCK=true  ynh_exec_warn_less pipenv install jupyterlab==$jupyterlab_version jupyterhub notebook jupyterhub-ldapauthenticator --three
 
 	ynh_exec_warn_less pipenv run jupyterhub upgrade-db