Most likely yes. Going down in voltage is less of an issue than going up. Don't go more than 3.3V, but 2.8V, 2.6, 2.4V might even work. You begin to have various ICs become inoperable. I think the ATtiny84 and microSD can both go pretty low. Looks like the WT2003S is min of 3V but I wouldn't be surprised if it went lower just fine.
Of course, don't install this in a medical device, but for general use should work fine.