With the latest snapshot 1.5.627.3, Vivaldi technologies has pushed the first delta update for Windows. Yes! Vivaldi is testing delta updates or new delta update based system for Windows, which saves your bandwidth and time.
Delta update is a small update, where only changes between two builds will be downloaded and applied instead of downloading the full installation. The latter happens to Vivaldi when you try to upgrade from any other build. For instance, you should be using Vivaldi snapshot 1.5.626.8 to get this small update.
Vivaldi team is planning to bring delta updates for Mac and Linux in the near feature. They’ve chosen Windows first for the new update system because ‘as it was relatively easy and impact most users’.