Psychtoolbox 3.0.21.0 “Fruity Aspirational Cashcow” 
was released at 31st March 2025.
You can download it as a zip file from the following link:
https://github.com/Psychtoolbox-3/Psychtoolbox-3/releases/download/3.0.21.0/3.0.21.0.zip
This marks the end of life and any and all support for Psychtoolbox 3.0.20,
what a short but eventful life it had! This release is strongly recommended
to upgrade to if you are a user of Psychtoolbox 3.0.20 on macOS or Windows,
as it allows most reliable and smooth use under the new paid software license
subscription model that launches today, the 31st of March 2025.
The complete development history can be found in our GitHub repository.
The release tag is “3.0.21.0”, with the full tree and commit logs under the URL:
https://github.com/Psychtoolbox-3/Psychtoolbox-3/tree/3.0.21.0
Compatibility changes wrt. Psychtoolbox 3.0.20.4:
- None.
Highlights:
-
Only improvements for license management for a hopefully smooth imminent start
of the new software subscription licensing model on Apple macOS and MS-Windows. -
We strongly recommend upgrading from Psychtoolbox 3.0.20 to 3.0.21 at your
earliest convenience if you are a macOS or MS-Windows user, which will require
a paid subscription license for versions 3.0.20 and later very soon! Previous
users of Psychtoolbox 3.0.20 will have until 14th April 2025 to buy a license,
as their free trial will run out during that day. New users will have a 14 day
free trial on a given machine until they have to buy and activate a license. -
This release is probably one of the very last ones, possibly the last one, to
support almost end-of-life Ubuntu 20.04-LTS or other Linux distributions older
than Ubuntu 22.04.5-LTS and equivalent, e.g., Debian GNU/Linux 12.0 (Bookworm).
All:
-
Improvements to license management via PsychLicenseManagement(); for imminent launch of the new software licensing business model on MS-Windows and macOS:
- Allow a configurable maximum offline time (grace period) of more than 30 days. Our licenses allow up to 120 days of offline time by default, but Psychtoolbox 3.0.20 had a hard limitation of 30 days max, so a license configured for 120 days would not work at all with Psychtoolbox 3.0.20. Therefore our licenses start off with 30 days maximum offline use, but can be extended to 120 days of offline use if all your licensed machines use Psychtoolbox 3.0.21 or later.
- Improved status messages for license related information.
- Built in “News” push message support. We can send short “poor man’s” SMS text messages to your machine for important news or information.
- Alpha quality support for offline “air-gapped” activation of licenses for select customers with special licenses - not the default for purchased licenses, and not something users are entitled to.
-
Various other smaller refinements, bug fixes and documentation updates.
Linux:
- Psychtoolbox was built and tested against Matlab R2024a and Octave 5.2 and later.
Windows:
- Psychtoolbox was built and tested against Matlab R2024a and Octave 7.3.
macOS:
- Psychtoolbox was built and tested against native Matlab R2024a and against native Octave 9.4 from HomeBrew, on macOS 13.7.4 Ventura for Intel Macs, and on macOS 14.5 Sonoma for Apple Silicon Macs.
Enjoy! And please make the Cashcow a happy cow soon. It likes cash. A lot. And nobody wants a sad cow, the world is sad enough without them being sad. Thanks! 
