The announcement of the Ionic 2 Release Candidate marks a significant milestone with major performance improvements and new features, including updates to Angular 2 Final and the introduction of the Ahead of Time (AoT) compiler for faster app performance. The release also introduces a new build process using Rollup, which optimizes code execution and reduces bundle size through tree-shaking, moving away from a Gulp-based workflow to NPM scripts inspired by Create-React-App. The updated app structure, informed by the finalized APIs of Ionic and Angular, recommends a new directory structure but remains flexible for customization. As the API has solidified, the Ionic team encourages the community to test the framework and report any issues, paving the way for the final release of Ionic 2.0.