As of January 2017 the latest Garmin GLO firmware version is 2.9.0; if you have an earlier version, you should update to use the GLO with iOS 10.
Garmin publishes a GLO firmware updater at:
http://www8.garmin.com/products/webupdater/howtoinstall.jsp
This installs the firmware updater on a PC. The Garmin WebUpdater program, when it is run after PC installation, recognizes the GLO when it is connected via USB and does the firmware update.
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