From SuperCollider wiki
New language features
- New Help.gui for much improved browsing+searching of SC's help docs
- Direct image manipulation in GUIs, thanks to the SCImage class (Mac only)
- New Scale and Tuning classes to facilitate the use of a wide range of tuning schemes
- "Modal" sheets/windows (used for e.g. preference panes) (Mac only)
New server features
- LocalBuf system - for extra convenience, synths can have their own "private" buffers which they maintain and free themselves
- Audio signals can now be mapped to SynthDef controls
- SuperColliderAU provides SC server as a Mac "Audio Unit"
- Scoping feature now has the ability to analyse the frequency response of filters (known to audio engineers as a "Bode plot")
- VDiskIn for variable-rate disk reading
- PartConv for efficient audio convolution
- BEQSuiteUGens (previously in sc3-plugins pack) for tasty filters
- PV_Div and PV_Conj for doing maths on FFT chains
- SendReply for sending OSC replies and array data back from the server
Other significant improvements
- Lots of effort gone into improving help documentation, especially for SC's GUI features
- Improved cross-platform GUI abstraction using "ViewRedirect", which now makes it very easy to create GUIs that can be used on all three main platforms
Improvements for various other things including MIDI, multichannel Buffer handling, audio I/O, FFT/IFFT, audio efficiency. Plus many little bugfixes and tweaks - see the ChangeLog for full details.
Many developers, users and documenters contributed towards polishing this new release of SuperCollider ("one of the largest open-source teams in the world" according to ohloh). On behalf of them all, we hope you like this argumentative essay!