The 1.90 version of TCPSyphonClient for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The actual developer of this free Mac application is TECHLIFE SG Pte. Ltd. The software lies within Internet & Network Tools, more precisely Network tools.
From the developer:
Syphon provides an ecosystem for sharing imagery between applications and new media development environments. Syphon is designed to be efficient and will not duplicate resources unnecessarily, keeping your frame rate and best interests in mind. Even on poor network environment it can carry out delivery without quality loss on image data.
You may want to check out more Mac applications, such as AquaEthereal, which might be related to TCPSyphonClient.