Details on the updates are here:

  • Increased the rate at which items spawn in world. Your chance of finding items should be significantly better now.
  • Zombie and animal population/ distribution adjustments.
  • Zombie and animal behavior fixes. Zombies should now react as expected
  • Server stability adjustments.

Source: https://forums.station.sony.com/h1z1/index.php?threads/h1z1-status-update-1-16.77/