I have never seen a stepper motor that could not use 24V. The 24V will not burn up the motors as long as the max current of 2.8A isn't exceeded.
As for the drivers, the A4988 is limited to 35V and 2A. If you use 24V you will be fine. Be sure to crank up the amperage to max. You may want to consider the DRV8825 drivers, which can handle up to 45V and 2.5A. These would be better suited to your motors. I personally would use those at 36V with current set to max. On these little drivers, they can/will get hot if running at/near max current, so they need a heat sink and likely a fan blowing across them to shed the heat. The DRV8825 are cheap and can plug into the same spot as the A4988. Here is a pretty good description of the two.
A4988 vs DRV8825 Chinese Stepper Driver Boards - RepRapWiki
If you already have the A4988, they will work, but at the reduced current and lower voltage, you will lose potential performance. If you have them, give them a try. The DRV8825's can always be put in there place later if you decide to.