Even though the README claims that XpartaMuPP and EcheLOn work with SleekXMPP 1.3.1 I noticed they don't work with SleekXMPP > 1.1.5. This patch makes them compatible with SleekXMPP >= 1.1.7 (1.1.6 is broken for other reasons).
P.S.: In case you want to look into the changes between the SleekXMPP versions: Apparently they messed up their git tags, so the tagged versions will show no differences. The Python packages on Pypi do however.