GemStone/S 64 Bit v3.4 is a major release with many optimizations and improvements, and GemBuilder for Smalltalk v8.3, as well as adding support for GS/64 v3.4, also includes many bug fixes and improvements. VSD v5.3.1 is updated with 3.4 definitions and includes a minor bug fix.
For more details, see the individual product pages, GemStone/S 64 Bit v3.4, GemBuilder for Smalltalk v8.3, and VSD v5.3.1.