3.0.0

Link titleThe 3.0.0 system update was released on June 19, 2017. This update was released for all regions.

Security flaws fixed: yes.

Change-log

This is the official changelog from Nintendo regarding this update:

Improvements Included in Version 3.0.0

Register a channel to receive News for specific games
To register, head to News > Find Channels
Add friends from your Nintendo 3DS and Wii U Friend Lists
To add friends, head to your My Page on the top left of the Home Menu > Friend Suggestions
Receive notifications when your Friends go online
To turn this ON/OFF, head to System Settings > Notifications > Friend Notifications
Find paired controllers within communication range by activating the vibration feature
To search, head to Controllers > Find Controllers
Change the user icon order on the Home Menu
To change order, head to System Settings > Users > Change Order
Select from 6 new Splatoon 2 characters for user icon
To edit your user icon, head to your My Page on the top left of the Home Menu > Profile
Change the system volume from the Quick Settings
To access Quick Settings, hold down the HOME Button
Lower the maximum volume for headphone or speakers connected to the audio jack
To lower the max headphone volume, head to System Settings > System > Lower Max Headphone Volume
This settings will be ON when Parental Controls are enabled
Change display colors to Invert Colors or Grayscale
To use this feature, head to System Settings > System > Change Display Colors
Use the Nintendo Switch Pro Controller via wired communication by connecting the USB charging cable
To enable, head to System Settings > Controllers and Sensors > Pro Controller Wired Communication
The NFC touchpoint on the Pro Controller will be disabled while the controller is using wired communication.
Update connected controllers
To update, head to System Settings > Controllers and Sensors > Update Controllers
Added a feature that suggests deletion of software data if there is insufficient space when downloading other software
To use this feature, head to System Settings > Data Management > Quick Archive
User save data is not deleted
General system stability improvements to enhance the user's experience, including:

Resolved an issue that caused game software updates to fail and prevented the software from starting
Improvements to prevent unintended HDMI input change with certain TVs while the console is docked in Sleep Mode

System Titles

It's unknown exactly what titles were updated.

NS-sysmodule

NS-sysmodule was updated, this fixed a vuln in multiple cmds.

OSS

The updated OSS includes a number of WebKit changes.

Sysupdate Required Error

Prior to v3.0, with the atumn and sun domains blocked, the system could be used with online services on non-latest system-versions fine. As of roughly the day following the release of v3.0 however, the system being on >=v3.0 is now enforced via an account-related domain. This affects everything using Nintendo-accounts, regardless of whether the current user has one linked or not.

This also affects launching the WifiWebAuthApplet on pre-v3.0. Error 2110-3400 is thrown while eShop is loading, with the conntest domain setup to trigger the web-applet(originally launching eShop could be used for triggering the WifiWebAuthApplet). When attempting to connect to wifi from System Settings, it will display the "Registration required ..." message then display a separate sysupdate-required message(different from the error message). With the dauth domain blocked, eShop has the same failure, however System Settings will launch the web-applet after it displays the "Registration required ..." message when connecting to wifi.