its not better to speculate anything about this 2500 Km figure now as it could be anything (assuming the stated figure is true) but it is very difficult to believe that its combat radius, as a sudden increase of 1100 KM in combat radius should be difficult without any design change, on the other hand if its Ferry Range then its a decrease of 500 KM ....
But if its Basic Range (only on internal fuel) seems possible as it will moderately increase the range about 700 KM, in current configuration JF-17 can carry upto ~2,500 litter internally both in (central fuselage & in wings) internal fuel carrying capacity may be improved in same way as Gripen NG (current capacity of 3,500 litter of NG from 2,000 litter C/D)
New arrangements of fuel tank & plumbing in central fuselage in JF-17
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Old arrangements of fuel tank & plumbing in central fuselage (for some PT aircraft)
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