Where to download the normal, officially released wallet software
We download Veil's officially released wallet software from Github, at https://github.com/Veil-Project/veil/releases but when there are new bug fixes or improvements committed to the "master" repository they may remain there waiting for some time for other upgrades before a new official release is made.
Where to download the latest, tested master software for the Veil wallet
Recently Veil has been using a service that Github offers enabling compiled versions of the software for testing or use, in Github Actions. https://github.com/Veil-Project/veil/actions
To choose the best version to download, simply read down the list looking for commits to the "master" branch. You will normally choose the most recent master build!
As you can see in these screenshots of things that have made it into the master build, there are numerous important fixes and improvements. (I skipped a few things that are not in the master yet.) You should also notice that the developer who makes the final commit is not always the one who did most of the coding in that piece. Finally, you can also see code that is committed to a branch that is not master, but which is a branch for a future release, such as RingCT staking code for a 1.2.0 release.
Downloading the latest master build
To reiterate, we are about to download the most recent master build. This is the one closest to the top of the list, marked as "master" in the blue highlighted label in the middle.
Click the name of the merge, for example "Merge #874: ..." which will load a screen showing the "Build for x86 Linux 64bit", "Build for Win64", "Build for MacOSX" and so on. You need to have and be signed into a Github account to get the actual downloadable files here! (Sign up and sign in to Github if you haven't already.)
If you click on your needed binaries (such as "macos-binaries" or "win64-binaries") it will immediately prompt a download. You can save them to your usual downloads folder and install these the same way as a normal wallet software release. If you click on the list at the left hand side it will show all the steps in the build and how long it took, and give you an "Artifacts" link near the top right hand side. If you click that, there will be a drop-down list of each of the appropriate downloadable binaries that you can choose from.
Basic principles when installing a new wallet version
There is no difference here than when you install a publicised Veil upgrade (official released version).
Aside from normal consideration to backing up your data, and always keeping a copy, or multiple copies of your wallet seed words and for convenience, your wallet.dat file, you don't have to do anything to your data folder when upgrading your software, so long as you are using a master build. (Don't try to use a build from another branch unless you know what you are doing, for example, you may run it on a testnet or devnet (development network) chain, with test Veil coins, not real, mainnet coins. In other words, the RingCT staking branch cannot be used on the main network until an upgrade of the main network is organised. At that time, it will be committed to the master branch in preparation for an official release.
Further support
Inevitably miners and stakers and other Veil community will be discussing the new versions on our Discord channel: https://discord.veil-project.com/
For specific issues affecting your wallet, which might involve details of particular transactions and amounts please submit those questions here on our Freshdesk Help system. https://veil.freshdesk.com/support/home