Vodafone has reportedly announced to offer free 4GB data on upgradation to Vodafone Supernet 4G. Vodafone users in Mumbai who upgrade to a 4G SIM card (with 4G handsets) can avail the free data. "Vodafone 4G SIMs are available at all Vodafone Stores, Vodafone Mini Stores or multi-brand outlets located across Mumbai," the company said in a statement.