Will "taking the phone off the hook" survive as an expression?* You can't really take the phone "off the hook" anymore, can you?
But it's a nice way to describe having a quiet night in with no intrusions. "I'm taking the phone off the hook and finishing this book I've been reading." "I'm switching my mobile off" doesn't have quite the same ring to it. [If you'll pardon the pun. And you probably won't. But that's outside my control so do as you will.]
*For the record, my survey sample of one - The Antiquer - says yes it will. But he was so busy trying to sort books he would have said anything to shut me up. He could be an unreliable source, if you see what I mean.