How can we connect our old Halo 3 stats and our current Halo 3/4 etc stats? The Master Chief collection doesn’t seem to update anything when I play.
If you are talking about importing your stats from the original Halo 3 into the MCC, then that’s not possible. MCC doesn’t have robust stat tracking like Halo 5 does, so beyond your PGCR, you won’t be able to review games you’ve played. However, Waypoint does track how many MCC games you’ve played, your global K/D, your highest rank, what intel/skulls you’ve unlocked, and what campaign missions you’ve completed. Updates may not be instantaneous, so try waiting awhile after playing before checking Waypoint to see if those stats updated.