Windows 1.0 Development Release 4

Windows 1.0 Development Release #4 was the fourth release in a series of Development Releases of Windows 1.0, which was distributed to developers on 31 August 1984. Photos of this build's installation media and release notes were posted by BetaArchive member Allosgroup on 8 July 2021.

According to the available release notes, this release has added support for cooperative multitasking, the ability to paint filled ellipses and rectangles among other GDI improvements, and Atom functionality. The MS-DOS Executive is still called the MS-DOS Window in this release according to the document.