Why does UART require CRC

[MichaelNordicUser]

In this app by Nordic

github.com/.../Bluefruit_LE_Connect_Android

a cyclic redundancy check (CRC) is added to the payload byte array before writing it to the UART receiving characteristic.

Is the CRC necessary? Doesn't the BLE stack add its own preamble, CRC, etc. to filter out noise?

Thanks

[FormerMember]

The app you link to is not a Nordic app, the Nordic apps can be found from Nordics github page: https://github.com/NordicSemiconductor, for the Android apps, search for android.