What's the difference between aci_gatt_update_char_value and aci_gatt_write_char_value?

[KKIM.6]

What's the difference between "aci_gatt_update_char_value" and "aci_gatt_write_char_value"?

In addition, what is "aci_gatt_write_without_resp"?

Is it faster than others to send data?

How can I active "aci_gatt_write_without_resp"?, because it is inactive in STM32cubeMX during the BLE setup.

[KKIM.6]

I'm reading PM0271 and I found the answer.

The update is used when the Server notifies a value to the client.

The read/write is used when the client wants to interact with the server.

Am I right?