proxy configuration for versions older than 20.

templates/keycloak.conf.j2

@@ -38,6 +38,9 @@ https-port={{ keycloak_https_port }}
 {% endif %}
 
 {% if keycloak_behind_reverse_proxy %}
+{% if keycloak_version is version_compare('22.0.0', '<') %}
+proxy=reencrypt
+{% else %}
 # The proxy address forwarding mode if the server is behind a reverse proxy.
 proxy-headers={{ keycloak_reverse_proxy_type }}
 {% endif %}