This software update can be downloaded by using Garmin Express. Please note that once a software update is released it can take up to 24 hours before Garmin Express provides this update to all users. This update can also be downloaded through the Garmin Connect Mobile app.
Changes made from version 2.60 to 2.70:
Correct issue which lead to increased standby current when device is powered down
Full Forerunner 235 Sensor Hub change log can be found here.