Fitch Ratings has upgraded Pakistan's Long-Term Foreign-Currency Issuer Default Rating to 'CCC+' from 'CCC'.According to Fitch, the upgrade reflects greater certainty over continued availability of external funding, in the context of Pakistan's staff-level agreement with the IMF on a new 37-month seven billion dollars Extended Fund Facility.It said that strong performance on the previous, more temporary IMF arrangement helped Pakistan narrow fiscal deficits and rebuild foreign exchange (FX) reserves, and further improvements are likely.Source: Radio Pakistan