With the most recent build of VaultWiki, we encountered the largest and longest running report volume of install problems ever. While the product page had mentioned that the product should be treated as unstable for a couple of days after a new build is released, a couple of days was never intended to turn into almost an entire week.
On top of that, there was no indication aside from a news entry of when the build was released, so customers could only try to figure out in their heads if enough time had passed for the ZIP to be considered reliable. Another option was to look at recent bug reports, and see whether a calm(ing) had been achieved for the most recent version.
However, none of this is sufficient, and a number of very serious bugs had appeared without warning, forcing us to release revision after revision of the software that for many users was impossible to keep up with. In the case of one of these bugs, we were unable to notify all of our customers by email, simply due to technical limitations - our outbox was flooded.
Today we implemented an "Unstable" flag that will appear next to new versions when you select one to download. This will appear when a new build is available and will remain for several days until a small number of customers have reported successful installs. If you don't want to take the risk of installing or upgrading at that time, simply wait for the "Unstable" text to be removed, or install the next latest version.
Again, we are deeply sorry for the confusion and headaches we and the product have caused in the past several days.