If my colors variable is:
[
{backgroundColor: '#e84351'}, // red
{backgroundColor: '#434a54'}, //grey
{backgroundColor: '#3ebf9b'}, //green
{backgroundColor: '#4d86dc'},
{backgroundColor: '#f3af37'}
]
My graph looks like so:

What is the way to set colors in the latest version?
Answer:
You need to do like:
[{backgroundColor: ["#e84351", "#434a54", "#3ebf9b", "#4d86dc", "#f3af37"]}]
Not documented, so I won't close yet
I'm not sure why ng2-charts doesn't just follow the Chart.js API and define the colors in the dataset. At the very least if the colors attribute isn't specified when declaring the component then the Chart.js API should still work instead of ng2-charts selecting default colors of you.
Took me way too long to figure this out, thankfully I found this, I was just about to create an issue here stating that colors in the dataset are ignored.
I agree that it would be ideal if the chartjs API still worked as documented
@beck24 So, what solution did you find?
See the comment above by @AmitMY
That's the solution
Full answer:
For a single data series, the coloring is:
[{backgroundColor: ["#e84351", "#434a54", "#3ebf9b", "#4d86dc", "#f3af37"]}]
For multiple data series, the coloring is:
[
{backgroundColor: '#e84351'},
{backgroundColor: '#434a54'},
{backgroundColor: '#3ebf9b'},
{backgroundColor: '#4d86dc'},
{backgroundColor: '#f3af37'}
]
Most helpful comment
Answer:
You need to do like:
Not documented, so I won't close yet