Support for G5 is now available in xDrip and xDrip+. For additional information, see xDrip with Dexcom G5 Support.
It is still suggested that those using xDrip with G5 request to join the xDrip G5 Facebook group:
Installing xDrip for G5
To get started, read the following thoroughly before attempting to run or use the application: xDripG5-Getting_Started