Installing the software
The software is available as a zip download.
I would recommend reading the !!Read_Me_First text file (which also tells you how to remove from your system). The Reporting Document tells you how to report any bugs you might find. Features gives you a nice overview and a clear idea of the objectives with this software.
When you are ready to try, Double-click on !Install and follow the prompts, rebooting your machine.
In use
The first indication that things have changed is that you have new options with Interfaces menu compared to previously.
You will also find that it has thoughtfully backed up your old version, just in case...
First impressions
I do not have an IP6 setup so my main interest was in updating my existing setup (and being generally nosy). For IP4, this is a drop in replacement. Everything works as before (feels subjectively faster) and it all works fine. Like all the best updates, it is very boring (it just works). RISC OS Developments have done an excellent job of making it all painless. While the software is still technically in beta, I have no issues running on my main RISC OS machine.
What is really exciting is the potential this software opens up of having a maintained and modern TCP/IP stack with support for modern protocols, TCP/IP 6 and proper wifi support.
RISC OS Developments website.