Windows 1.0 Development Release 1

Windows 1.0 Development Release #1 was the first release in a series of Development Releases of Windows 1.0, which were distributed to application developers throughout 1984.

The first of these was probably compiled sometime in May 1984, possibly on 29 May 1984 if the date in DR5's  is indeed a leftover from this build. An article in the 7 May 1984 issue of InfoWorld magazine claims the first version for developers would be released towards the end of May 1984, further supporting the theory that the Development Release stage started around May 1984.

Another article in the 19 November 1984 issue of InfoWorld claims developers have been recieving monthly releases since May, providing further evidence that the DR phase began in May 1984.

This build is also probably the same build as the earlier Tandy 2000 build.