Following concerns about the potential for Formula One cars to shift gears automatically without any driver input (i.e., a fully-automatic transmission), mandatory software was introduced in 1994 that ensured that gear changes only occurred when instructed by the driver. Pre-programmed, computer-controlled, fully-automatic upshifts and downshifts were re-introduced and allowed from 2001, and were permitted from that year's Spanish Grand Prix, but were banned again in 2004. Buttons on the steering wheel to skip directly to a particular gear (instead of stepping through the gears using the paddles) are also permitted. Formula 1 cars currently use mandatory 8-speed paddle-shift gearboxes, being increased from the previous 7-speed gearboxes, for the 2014 season. The 2005 Minardi PS05, Renault R25, and Williams FW27 were the last Formula 1 cars to utilize a 6-speed gearbox respectively, before the switch to a mandatory 7-speed gearbox for the 2006 season.