Version 10 (Peregrine) debuted in a first beta version on June 3, 2009 and scored 100/100 on the Acid3 test, but failed the smoothness criteria. There was also a preview build that scored 100/100, released on March 28, 2009. Among other features, it also came with speed optimizations, inline spell checking for forms, an auto update feature, HTML mail formatting, web fonts and SVG font support, alpha transparency support using the RGBA and HSLA color models, and an updated version of the Opera Dragonfly web debugger. Opera Turbo, a mode which uses Opera's servers as proxy servers with data compression, reducing volume of data transferred by up to 80% (depending upon content), and thus increasing speed, was introduced.