Arvopia 0.5 is the Foliage update. It had a main focus on plants, as the name suggests, and it made some environmental changes.
The original tree tiles were removed in favor of an entity tree similar to rocks and flowers. When you break a tree, it drops wood. In addition to trees however, there is the addition of grass, ferns, and dandilions that spawn ontop of grass tiles.
Static entities, that is those that don't move, are now given health. Their healthbar is shown similarly to non-static entities, however it does not display a value like it does with creatures, but more of a progress bar.
In the options menu, the Scale slider was removed and replaced with a Toggle Button for whether or not the game will pause itself when the mouse leaves the game window. In addition to a new option, the ability to save and load a world was added, allowing people to keep their progress.
Branching off from Arvopia 0.4, version 0.5 introduced sunsets and sunrise colors into the game to spice up the lighting system.