1. I found two changes that will make CombatTracker work in WoW 6.0.2 (tested on PTR client).

    1. All CombatTrackerFrameText:SetText calls should be replaced by CombatTrackerFrame_Text:SetText

    2. GetNumPartyMembers() function used in CombatTracker_ReportDPS() was removed in 5.0.4 patch. You can use GetNumGroupMembers() or IsInGroup() function instead:

        if IsInGroup() then
        SendChatMessage(msg, "PARTY")
        else
        print(msg)
      

    or

          if GetNumGroupMembers() > 0 then
          SendChatMessage(msg, "PARTY")
          else
          print(msg)
    

    Enjoy!