Windows 3.0 build 13

Windows 3.0 build 13 is an unleaked build of Windows 3.0, which was found in an antitrust document dated 1989-02-08. WINOLDAP.MOD from build 55 contains the following string: Microsoft Windows Old Application Support Module (3.00.14.20jan89) This suggests that build 14 was already compiled around 1989-01-20. Therefore, build 13 was almost certainly also compiled in 1989-01.