@Laoel, I know what the problem is. You have currently the latest Snapshot installed that was realeased before the 1.0 Stable. Basically that last snapshot was the same as the Stable, but they set it that if you are using one of those builds, then you are in the Stable stream and don't recieve shapshot updates anymore. The snapshots are were new features are added. If they are stable enough, they will release a new stable release and then you will be prompted to update Vivaldi in your case (= if you are in the stable stream currently). If you want following the the new snapshots (which might contain new bugs since those are experimental builds like I said) and thus have the newest features dirctly, then you have to download the latest snapshot (see links above) and install it over the Vivaldi you have now (no need to uninstall first). But keep in mind that if you want to go back then to the stable (idk why you should do that but anyway), it can be the case that you lose your bookmarks then, since the profiles doesn't match. But to upgrade now from stable to snapshot, it shouldn't be a problem. I'm using the snapshots btw and no real problems so far, and if there are some, they are fixed within a week or so.
Hope this helps!
Hope this helps!