Diet Coke
Diet Coke does not use a modified form of the Coca-Cola recipe, but instead an entirely different formula. The controversial New Coke, introduced in 1985, used a version of the Diet Coke recipe that contained high fructose corn syrup and had a slightly different balance of ingredients. In 2004, Coca-Cola introduced Coca-Cola C2, which it claims tastes much closer to Coca-Cola but contains half the carbohydrates. In 2005, the company introduced Coca-Cola Zero (replaced by "Coca-Cola Zero Sugar" in 2017), a sugar-free variation of regular Coca-Cola.
Afri-Cola
However, the new recipe was unpopular (as with New Coke). The mixture was again changed to taste more like the original one, the caffeine content was increased in 2005 to around 200 mg/L and caffeine was again listed as an ingredient on the label. This mixture was also not sufficiently successful and on April 1, 2006, the company finally changed back to the original recipe, with caffeine content of 250 mg/L.