The 2.3.0 system update was released on May 15, 2017. This update was released for all regions.
Security flaws fixed: unknown.
This is the official changelog from Nintendo regarding this update:
Improvements Included in Version 2.2.0
- General system stability improvements to enhance the user's experience
It's unknown exactly what titles were updated, however the browser was not updated going by the WifiWebAuthApplet user-agent.