Just tried to update my CGM subscription via Medtronic eShop Wouldn't let me add another 12 month subscription so I called them - got told they are now shipping the Sensor3 for 640g as it's a better sensor, smaller, more comfortable and now lasts up to 7 days. Oh and quicker start up time. Can't say they old ones were uncomfortable, but the >2 hour start up annoyed me greatly. I know many people "hack" the system and get a bit more life out of the sensors, but my experience has been hit and miss, usually getting a couple at best of days extra but with questionable accuracy. Anyone with experience of the new sensors with the 640g system?