I would like to suggest to add some corner radius to events. This will improve the ability to distinguish between events and background, make a stronger implication for a beginning or end of an event, and help differentiate between an overlap between events or an end of one and a beginning of the other.

Generally corner radius helps to clearly define The "inside" and "outside" of elements.

On another note, this will make the app feel more modern and pleasant to use as sharp corners feel more "painful" (see Steve Jobs quote on the matter).

I suggest 4/8 px radius to maintain the "blocky" look & feel.

Round edges, just like in business calendar 1

I would love to see a more Material Design consistent UI. Round icons and rounded corners for the widgets, would both be appreciated features and would help keep the look of people's phones consistent. The beauty of Android is customization, and for most people that includes consistent aesthetics, as well as function.