GemBuilder for Smalltalk v8.7.1 is a maintenance release that adds support for Cincom VisualWorks 9.3, 9.3.1, and 9.4, and for Windows 11.
Note that testing with VW 9.4 and Windows 11 was not completed until after the release, and are not in the Release Notes/Installation Guide; for complete compatibility details, see The GBS 8.7.1 Compatibility table.