Is it possible to support notify and indicate via same characteristic simultaneously?

[TylerD]

I can easily generate a custom service that has characteristic with both notify and indication enabled. If I test with mobile app (using nRF Connect or other mobile apps for Android) it seems that I can only enable notifications or indications, but not both at the same time.

If I enable notifications first and then try to enable indications, then notify is automatically disabled. And same thing the other way around.

In other words, I can only write value 0x1 or 0x2 to the CCCD, but not 0x3. (I did not try to write directly to the CCCD yet).

Is this a limitation in the Bluetooth specification or just a limitation in the mobile app (or perhaps Android BLE stack?)

[chrysn]

Note that while it is possible to do this with Nordic devices, PC-style peers may easily *not* support this.

By the discussion in https://github.com/hbldh/bleak/issues/526, it seems that Linux bluez and MacOS don't even have the APIs to select whether to receive notifications or indications on a characteristic, let alone support running both at the same time.