New Delhi: Oil companies are upgrading their fuel dispensers to ensure they display correct prices when rates reach Rs 100 per litre. The move comes amid a relentless rise in global crude oil prices although oil companies do not expect petrol rates to reach three-digit levels soon.Most pumps do not need to upgrade but some have old dispensers that can only display prices in two digits before the decimal point, which would make them obsolete if petrol price rises another Rs 10 a litre, said people aware of the matter.A few petrol pump dealers had raised doubts over the ability of the current dispensers to show three-digit prices, they said.Petrol price rose to Rs 90.22 a litre and diesel Rs 78.69 in Mumbai on Monday. In Delhi, petrol and diesel were sold for Rs 82.86 and Rs 74.12 a litre, respectively.