From a exobiology / worldbuilding mailing list:
Based on a bolometric luminosity of 0.000525 Suns for Trappist-1, only planets “d” and “e” are clearly in the conventional habitable zone, planets “c” and “f” would be marginal, and the others either too hot or too cold by conventional habital zone criteria. But, if planets f, g, and h are tide-locked, their substeller points might be warm enough for liquid water with the rest of the planet frozen. Despite its terrestrial mass, planet “b” seems to have an extensive envelope–perhaps Venusian in character and with 4.3 times terrestrial insolation at wavelenths that are more effective at heating than the Sun’s, it is not a good prospect for liquid water. These new numbers make planet “c” somewhat denser than Earth, but the others are significantly less dense. There is other evidence of an envelope around planet c (hydrogen spectroscopy).