Do NOT use your booster seat after nine (9) years from the date of manufacture. The date of manufacture for Olli can be found on the label on the bottom of the frame which is underneath the seat cover. For Oobr the date of manufacture can be found on the underside of the seat base.o NOT use your booster seat after nine (9) years from the date of manufacture. The date of manufacture for Olli can be found on the label on the bottom of the frame which is underneath the seat cover. For Oobr the date of manufacture can be found on the underside of the seat base.