There is a grace period of 3 months if you applied before the date of expiry and the you have the proof (the RMR receipt issued) and the driving licence card.
If you have lost this receipt, the DLTC can issue you with a duplicate receipt free of charge.
Also note regulation 108(6) of the National Road Traffic Regulations, 2000. It was added in September 2003 and amended in 23 July 2004.
(6) (a) Notwithstanding the provisions of subregulation 5(a), where a person has applied for a new driving licence card in the manner contemplated in subregulation 5(b) on or before the expiry date of the driving licence card held by such person and a driving licence of the person concerned has not been suspended or cancelled, that card shall remain valid until the new driving licence card has been issued in terms of subregulation (3) but not for more than three months after the expiry date of such driving licence card.
(b) The provisions of paragraph (a) shall only apply if the holder of the driving licence card is in possession of the driving licence card previously issued to him or her and proof of the fees paid in terms of Regulation 109(2)(c) for a new driving licence card as contemplated in Regulation 108(1).
[Subreg. (6) inserted by R.33(c), GNR 1341 w.e.f. 26 September 2003]
[Subregs (5) and (6) amended by R.19(b), G.N. R.881 w.e.f. 23 July 2004]