The latest version of Vivaldi sports a reworked browsing history, and better control over audio, as well as several bug fixes. The release announcement lists all the changes. None of the changes appear to be related to security.
Vivaldi 1.8’s new history interface is a real improvement over what’s available in other browsers. Anyone who spends a lot of time reviewing their browsing history will appreciate the new calendar view.
Despite the improvements, I’d rather the Vivaldi development team spend their time fixing issues with the user interface. The sidebar bookmark editor is still weirdly difficult to use, and it’s also now apparently impossible to remove. There are still inconsistencies in the way links and bookmarks are handled, and the browser still lacks options that would allow complete control over whether links and bookmarks open in new tabs.
Update 2017Apr05: the full version number is 1.8.770.50.