Currently, there is no option to upgrade your ThinCharge. Your ThinCharge is already upgraded to the newest software. Please disregard the misprint on the inside of the ThinCharge that states, "Please visit www.thinchargecase.com to upgrade software when charging is abnormal (windows only)".
If you are having charging issues, please take the following steps to ensure that your ThinCharge is working correctly.
Take the phone out of the ThinCharge and then reinstall it, creating a hard reset.
Make sure that your phone is inserted all the way into the case. If not connected tightly it will cause connection issues when trying to charge.
Also, make sure to reboot your iPhone by holding down both the home and power button at the same time until the phone resets, then continue the steps to reinstall your phone.
Please make sure to charge the case by itself (without the phone inserted) using your iPhone charging cable for about 3-6 hours to ensure that the case is fully charged.
After completing all these steps and you are still having issues, please follow the steps to submit a warranty claim to request a replacement: https://support.chargetech.com/hc/en-us/articles/115000639628-Submit-a-Warranty-Claim-