Compiled binaries will be available from the same link once they have been uploaded. https://github.com/PIVX-Project/PIVX/releases/tag/v4.0.0rc1
Basically, this is a testnet-only build specifically to upgrade our main public testnet to the new 4.0 network before releasing the final mainnet release. So the plan is to upgrade our main public testnet to 4.0 first using this RC build, ensure that the fork goes smoothly, squash any last-minute bugs, then release the final core wallet for the mainnet if all is well before the end of year. So those running PIVX 3.x testnet nodes should upgrade soon as there will be a hard fork at block 1347000, expected to occur before the end of this week.
We encourage everyone to download and try out the 4.0 rc1 testnet wallet to get familiar with the new user interface. If you have any issues or want to report bugs, you can do so in the #pivx_testnet channel.
If you need some tPIV testnet coins, you can get some from here: https://faucet.pivx.link/
We will be loading a few howtos along the way for some of the key features. First being Cold Staking.
Not long to go for the final 4.0 release!