▁is ▁not ▁compatible ▁with ▁the ▁d BASE ▁III + ▁format . ▁ ▁d BASE ▁III + ▁– ▁MS - D OS ▁( Level ▁ 3 ) ▁this ▁starts ▁the ▁modern ▁era ▁of ▁d BASE ▁. d bf ▁files . ▁The ▁d BASE ▁III + ▁was ▁introduced ▁in ▁December ▁ 1 9 8 5 ▁when ▁the ▁product ▁was ▁released . ▁▁▁ 1 6 - bit ▁version ▁finally ▁released ▁in ▁April ▁ 1 9 8 3 ▁version ▁ 2 . 4 ▁ ▁Str ucture ▁layout ▁of ▁the ▁file ▁type : ▁ ▁d BASE ▁IV ▁– ▁MS - D OS ▁( Level ▁ 4 )' ▁▁ 1 . 0 ▁x 3 2 2 ▁Oct ▁ 1 9 8 8 ▁▁ 1 . 0 ▁x 5 5 ▁Mar ▁ 1 9 9 3 ▁– ▁d BASE ▁Comp iler ▁▁ 2 . 0 ▁x 1 2 ▁Oct ▁ 1 9 9 3 ▁In cludes ▁fixes ▁in ▁d BASE ▁IV ▁v 2 . 0 ▁x 1 6 ▁above ▁( not ▁x 1 7 ▁i . e . ▁not ▁V LM ▁compatible , ▁d B 5 D ▁ex e ' s ▁are ▁compatible ). ▁It ' s ▁also ▁a ▁new ▁version ▁that ▁contain ▁new ▁features ▁not ▁in ▁the ▁V 1 . 0 ▁product : ▁▁ 3 2 - bit ▁generation ▁ ▁Auto ▁compiling ▁and ▁linking ▁ ▁Sm aller ▁. EX E ▁size ▁ ▁Menu ▁driver ▁user ▁interface ▁ ▁Link er ▁can ▁produce ▁combined ▁. DB O ▁output ▁ ▁Link er ▁can ▁produce ▁a ▁. MAP ▁file ▁ ▁Comp iler ▁supports