Latest firmware is 2018-02-02.

Read the firmware upgrade page on the support website to learn how to upgrade.

To upgrade from the HotSpot web interface (method A - recommended), first download this zip file: firmware.bin and follow the instructions here.

To upgrade using a microSD card (method C), first download this img file: flasher.img, burn it to the card using Etcher and then follow the instructions here.

For the records, the past firmwares 2017-09-09, 2017-10-31, 2017-11-19, 2017-12-05, and 2018-01-01 are still available.