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There are two types of firmware information notices, an "update" (fixes) and an "upgrade" (new feature), the latter referring to the Airplay "upgrade" which can be done after you're able to successfully "update" the firmware. If you don't have a "wired" connection from the AVR to your router, ideally that is what's best for firmware updates/upgrades. Regardless, as noted in the Owner's manual p. 106, either press/hold the ON/STANDBY button for more than 5 seconds, or unplug the AVR for a few minutes at which point the AVR will attempt the update again.
Also note there is a dedicated Denon AVR-4311CI Owner's thread ---> http://www.avsforum.com/t/1274153/the-official-denon-avr-4311ci-avr-a100-thread-no-price-talk/0_50
There are two types of firmware information notices, an "update" (fixes) and an "upgrade" (new feature), the latter referring to the Airplay "upgrade" which can be done after you're able to successfully "update" the firmware. If you don't have a "wired" connection from the AVR to your router, ideally that is what's best for firmware updates/upgrades. Regardless, as noted in the Owner's manual p. 106, either press/hold the ON/STANDBY button for more than 5 seconds, or unplug the AVR for a few minutes at which point the AVR will attempt the update again.
Also note there is a dedicated Denon AVR-4311CI Owner's thread ---> http://www.avsforum.com/t/1274153/the-official-denon-avr-4311ci-avr-a100-thread-no-price-talk/0_50