The Pebble SDK 2.0, introduced on November 6, 2013, includes major updates for developers with new tools, an overhaul of the SDK, and enhanced APIs for building applications. Key features include a simplified build system, improved documentation, dynamic memory management, and event-driven programming patterns, as well as the integration of JavaScript for broader application capabilities. Developers are encouraged to migrate existing apps from Pebble 1.0 to 2.0 due to incompatibility and to utilize the new frameworks for better app functionality.