This is the final release of the version 3.1.2.
Many new features and bug fixes have been added since the version 3.1.1.
If you want to explore the list of features, you can view the comparison table on the special webpage of Upload Extensions.
The extension has been released in the official Customisation Database on phpbb.com: https://www.phpbb.com/customise/db/extension/upload/.
Please use the dedicated support area or Issues section to receive support for this version.