We do not know, however, there have been some troubling speculations based on what we presume to have happened long ago during the Big Bang. When the universe was still less that 1 second old, it probably underwent several 'phase changes' or 'freezings' as the physical laws by which particles and forces act, changed. We can uncover some of this change in our accelerator labs at CERN, Stanford and Fermilab so we are pretty certain that it happened in a big way when the universe was starting out.
Some cosmologists have speculated that, in the future, the universe may undergo yet another 'phase change' as some new physical state begins to nucleate and form bubbles of a new phase within the space of our current universe. These bubbles will start smaller than an atom, and expand at the speed of light eventually after billions of years to merge with their neighbors. By that time there will be little left of the regions of space where our laws of physics work, except perhaps string-like regions of spacetime.
Now, the next round of changes MAY not be all that spectacular because there is not much energy left in the universe which already has a temperature only a few degrees above absolute zero. There is little wiggle room to shove a new energy state under this particular rug. The change might involve an almost imperceptible change in the law of gravity by a few percent, or a very weak new quantum effect. No one knows. But consider this. If ANY of the dozen or so fundamental constants were to change by less than 1 percent from their present values, life might be made impossible as atoms become slightly more well-bound in molecules for them to be broken apart in life-sustaining chemical reactions.
Don't loose any sleep over this, on the other hand, this could happen tomorrow, or a hundred billion years from now. I would still buckle my seat belt and stop smoking as precautions to far more likely kinds of death!