There are currently no plans for a Linux version of the Dayturn viewer; primarily because of the very small potential user base.
The latest version of the KokuaOS viewer (that predates the Dayturn viewer) can be downloaded from SourceForge at the following links:
KokuaOS 4.2.1 32-bit
KokuaOS 4.2.1 64-bit
The latest version of the KokuaOS viewer (that predates the Dayturn viewer) can be downloaded from SourceForge at the following links:
KokuaOS 4.2.1 32-bit
KokuaOS 4.2.1 64-bit