Apple Inc. is probably working on the new technology of mouse and keyboard, which have not been changed much since 2009 (in fact, Wireless Keyboard has not been changed for more than 6 years). In recent FCC filings, changes have been presented for both Magic Mouse 2 as well as Wireless Keyboard.
Though external design has not been shown in the filings, internal upgrade is probably on the way. The peripherals of the device(s) are moving up from Bluetooth 2.0 to the better Bluetooth 4.2 standard. It is also moving from AA batteries to built-in lithium-ion packs, so that the consumer would not have to change the batteries again. It is not clear when the company will release the devices, but it is expected that they will come with new Macs this year.
Source: FCC (Magic Mouse 2), (Wireless Keyboard)