As part of the upgrades, the company has revised its trim levels for the car, replacing the current T2 and TR trim designations with new levels dubbed Active, Icon, Icon Plus and Trend.
Entry-level Active Yaris comes with a six-speaked audio system, auxilliary and USB audio connections, electric front windows, stability control and traction control.
Icon specification adds 15-inch alloy wheels, Toyota's touch multimedia system, air conditioning and a rear-view camera. Icon Plus upgrades the Yaris with front fog lights, automatic wipers, dual-zone climate control and cruise control. Top-spec Trend specification includes larger 16-inch alloy wheels, rear privacy glass, chrome detailing around the door mirrors and leather handbrake and steering wheel trim.
As well as the specification changes, Toyota has also updated its 1.4-litre D-4D diesel engine, bringing its official CO2 emissions down to 99g/km. That change puts the Yaris 1.4 D-4D in Band A for road tax, while Toyota says improving the economy of the engine from 72.4mpg to 74.3mpg combined will save owners money at the pumps.
A number of option packs have also been introduced for 2014 models, with a Smart Pack adding keyless entry and push-button stats for £300, and a Protection Pack adding front and rear parking sensors, floor mats, mud flaps and black side mouldings for £700.
Icon Plus and Trend versions of the Yaris can also be upgraded with Toyota's multimedia system, which features Google search functions alongside satellite navigation, for £650.
The Yaris Hybrid also adopts the new specification structure, doing away with current T3 and T4 trim levels.
Prices for the MY2014 Yaris start at £10,895 for a 1.0-litre VVT-i in Active trim, rising to £15,995 for a 1.3-litre VVT-i in top-spec Trend trim. Prices for the MY2014 Yaris Hybrid start at £15,495, rising to £17,495 for a high-specification model. Both vehicles are on sale now.