Arduino Boards Manager: Cannot select release V1.0.0

Cannot select CubeCell Release V1.0.0 in Arduino (1.8.12) Boards Manager.
Where is the problem?ArduinoBordsmanager

Hi It has not been release as a board manager yet. I would follow the instructions in Heltec github and down load to your IDE hardware file.

You need clear the cache of Arduino environment, it’s in C:\Users\username\AppData\Local\Arduino15.

If there is no particularly important files in this path, everything in the Arduino15 folder can be deleted.

Great, it worked. Thanks for the quick help.