Nintendo has released firmware version 12.0.0 to the Switch and Switch Lite, upgrading the pair from version 11.0.1 that arrived last year. Version 12.0.0 is a fairly innocuous update despite its number jump. According to the patch notes, the update addresses an issue in version 11.0.1 that interrupted a console from automatically backing up save data.
However, the SwitchBrew community and @OatmealDome have discovered some noteworthy changes as of version 12.0.0 that Nintendo did not mention in its patch notes. According to SwitchBrew, Nintendo has added '4kdp_preferred_over_usb30', which has a 'false' default value. All Switch consoles output video using DisplayPort Alt via their USB Type-C ports, albeit currently at up to 1080p. Hence, it is not much of a stretch to read the new setting as 4K DisplayPort preferred over USB 3.0.
Additionally, version 12.0.0 adds 'is_crda_fw_update_supported', which @OatmealDome believes allows the Switch to update its dock's firmware. Nintendo has never updated the Switch's dock in its lifetime, though. Supposedly, 'crda' means 'Cradle for Aula', with Aula being the codename for a new Switch model. So, it seems that Nintendo will be able to update Aula's dock, but there is no other information about its functionality at this stage.
Moreover, Nintendo has added audio support to its Bluetooth driver with version 12.0.0. Currently, no Nintendo Switch offers Bluetooth Audio natively, although its Joy-Cons use Bluetooth. There is no guarantee that Nintendo will bring this functionality to a future Switch console, but it would seem odd for the company to add support for the feature so late into the Switch's lifecycle.
In short, the changes that version 12.0.0 makes to the Switch's firmware suggest that Nintendo is working on a new console. Rumour has it that the next Switch will utilise NVIDIA DLSS to reach 4K, but there is nothing within version 12.0.0 to suggest that DLSS is incoming for Nintendo's next handheld console.
Source(s)
SwitchBrew via @OatmealDome (1) (2) (3), Erik Mclean - Image credit