The lander is now in sleep mode, keeping "all instruments and most systems on board shut down." Thankfully, engineers managed to gather all the collected comet data before Philae's batteries were depleted. If we're lucky, it may wake up when it gets closer to the Sun.
From now on, no contact would be possible unless sufficient sunlight falls on the solar panels to generate enough power to wake it up. The possibility that this may happen was boosted this evening when mission controllers sent commands to rotate the lander's main body, to which the solar panels are fixed. This may have exposed more panel area to sunlight.
In case you haven't been following the complete drama of a little machine on a ball of ice and rock 300 million miles away, a couple pieces of Philae's landing gear didn't work. It touched down but then bounced twice, eventually ending up in the dark shadow of a cliff. Philae's solar panels weren't getting enough sun, and when the initial charge on its battery ran out, it went dark, long before its planned March 2015 end date.