Nokia just let loose firmware version 21.0.045 that promises to improve call reliability and internet browsing while smoothing out the jumpiness some have seen with kinetic scrolling introduced in v20.
The software version number will be 21.0.045 (RM-505) or 21.2.045 (RM-507) depending on your region. The release for N97 China 2G (RM-506) will follow shortly. Non-customised versions of the software, with country (SIM-free) and operator versions following over the next few days and weeks.
The update is only available via Nokia Software Updater (PC). OTA will be slightly delayed as this package is a little bigger than normal with apparently a wealth of new content available.