GemStone/S 64 Bit v3.6 is a major release, including support for encrypted extents, new special data times, along with other new features and optimizations.
GemBuilder for Smalltalk v8.5 and 5.4.6 are new releases that add support for GS/64 v3.6 as well as other enhancements and bug fixes.
For more details, see the individual product pages, GemStone/S 64 Bit v3.6, GemBuilder for Smalltalk/VW v8.5, and GemBuilder for Smalltalk/VA v5.4.6.