Occasionally, changes and improvements to the system software (firmware) on the @boardname@ are needed. Updates to the firmware are made by the micro:bit Education Foundation.
Changes to the firmware don't happen very often. You probably don't need to update it for your @boardname@ if everything is working alright. Sometimes there's a problem with a certain part of the board not working right or it has trouble connecting to your computer or other device. In those cases, a firmware update may include a fix for the problem.
Instructions for updating the firmware are shown on the firmware upgrade support page at microbit.org.