Atom now ships with the 1.0 API enabled and no longer loads packages that use deprecated APIs. You can run Atom with --include-deprecated-apis to still load them but the APIs will be completely removed in the upcoming 1.0 release.
Atom now has built-in support for preview tabs. Check the Use Preview Tabs option from the Tabs package settings to enable. Tabs will be reused across opened files unless they are edited or double clicked. You can also run tabs:keep-preview-tab from the Command Palette to retain the tab.
Switched to a tiled rendering strategy to improve text editor rendering performance, especially scrolling.