tl;dr: Except for the signal being 3x larger, at this point nothing new has been learned.
The only thing new I can see is that the signal is 3x larger than the previous one recorded by Curiosity, removing any potential lingering doubt about the reality of signal, which at only 7 ppb was close to the error bars.
Now at 21 ppb (3x larger than the 2013 whiff shown in the image above) it stands out clearly.
So except for the signal being 3x larger, at this point nothing new has been learned.
NASA JPL News item from June 23, 2019 Curiosity's Mars Methane Mystery Continues says
The finding suggests last week's methane detection - the largest amount of the gas Curiosity has ever found - was one of the transient methane plumes that have been observed in the past. While scientists have observed the background levels rise and fall seasonally, they haven't found a pattern in the occurrence of these transient plumes.
"The methane mystery continues," said Ashwin Vasavada, Curiosity's project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. "We're more motivated than ever to keep measuring and put our brains together to figure out how methane behaves in the Martian atmosphere."
Curiosity doesn't have instruments that can definitively say whether the source of the methane is biological or geological. A clearer understanding of these plumes, combined with coordinated measurements from other missions, could help scientists determine where they're located on Mars. (emphasis added)
The first lines of the New York Times' With a Poof, Mars Methane Is Gone sums it up nicely as well:
Last week, NASA’s Curiosity rover detected a belch of natural gas on the red planet. The gas has since dissipated, leaving only a mystery.
Mars gave a good burp last week, but the gas has come and gone, leaving scientists no closer to knowing whether there is life on or beneath the red planet.
There are still at least two completely different possible sources of atmospheric methane on Mars and the current data does not help to distinguish between them.
From Phys.org's A Martian methane belch melts away:
One leading theory is that the methane is being released from underground reservoirs created by long extinct life forms.
Though Mars has no active volcanoes like on Earth, it is also possible that methane is being produced by reactions of carbon from carbonate rocks or carbon dioxide, with hydrogen from liquid water. (emphasis added)