APK 2.5
https://bubbletech.ca/FlexSpec_Backpack_2_5/Flexspec.Backpack-Signed.apk

APK 3.8
https://bubbletech.ca/FlexSpec_Backpack_3_8/Flexspec.Backpack-Signed.apk

APK 3.10
https://bubbletech.ca/FlexSpec_Backpack_3_10/Flexspec.Backpack-Signed.apk

Tips for Installation on Android devices

• • To install the app, the device must allow installation from unknown sources.  To allow apps to be installed from unknown sources, go to Settings->Security and then find “Unknown Sources” in the list of available options and enable it.
  •  If using Android 6, ensure the email client and default PDF viewer that the device uses has permission to access storage.  Go to Settings->Apps and then find the email client and PDF viewer in the list of installed apps (Android uses Gmail for email and Drive for PDFs as default).  Select the app from the list and then select “Permissions” and enable the “Storage” option.
  •  Also, please ensure the device’s Location service is running.  The option for enabling it is in Settings->Location.