Some of the improvements include:

• The Derivative command (and hence the Tangent Tool) are now working for all functions (rather than just polynomials as before)
• Integration now works for most common functions (not just polynomials as before)
• The Spreadsheet is now working for simple copy & paste operations (the spreadsheet tools aren’t implemented yet)
• Double-click to redefine and the right-click menus now work in the Graphics View
• There are now more options for loading and saving. As well as uploading directly to GeoGebraTube you can open directly from Google Drive. You can now also save and load .ggb files locally.
• The Chrome App is now working in the same languages as GeoGebra 4.2, so try it out in your language!