2G with Khalid map or Daotong map is redundant, so there is absolutely no need to change 4G cards. It is suggested that the landlord go to the designated store of CASDA or solve it after sale. Don't listen to other people's bluff. As for the landlord who wants to change the 4G card, it is also possible. Just buy a Chuangjian brand 4G universal speed card.