Sails v0.12 comes with an upgrade to Socket.io and Express, as well as many bug fixes and performance enhancements. You will find that this version is mostly backwards compatible with Sails v0.11, however there are some major changes to sails.sockets.* methods which may or may not affect your app. Most of the migration guide below deals with those changes, so if you are upgrading an existing app from v0.11 and are using sails.sockets methods, please be sure and carefully read the information below in case it affects your app. Other than that, running sails lift in an existing project should just work.
Upgrading from 0.10 or 0.11?
The v0.12 release of Sails contains a few breaking changes which affect userland. To read the v0.12 migration guide, click here.