Changes:

• For those of you wondering, here is how the “X”s are different.
  • ”X”s are a deep shade of red (instead of white)
  • ”X”s are 1.5 times as big
  • ”X”s are displayed for approximately 4 seconds at death location (instead of being tied to the Spartan’s body), even if the player respawns prior to 4 seconds (instead of disappearing instantly or within 2 seconds)

Sources: 1

– Chief Landless

Geronimo!