https://devzone.nordicsemi.com/f/nordic-q-a/67544/why-can-notifications-get-sent-before-they-are-enabled-if-devices-have-been-previously-bondedI&#39;m developing a Peripheral with a rather intricate connection process and doing a lot of testing. I find that if a Central connects, and then the Peripheral tries to send a notification via sd_ble_gatts_hvx() before the Central has enabled notificationsen-USTelligent Community 13Mon, 26 Oct 2020 11:36:19 GMThttps://devzone.nordicsemi.com/thread/276841?ContentTypeID=1Mon, 26 Oct 2020 11:36:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:08c0b851-7608-41de-a55b-8e1bab05a48fmrono<p>The server needs to remember if a bonded client has enabled notifications earlier. So if the central left the notification enabled when it last disconnected, then it will be enabled automatically upon re-connecting.</p> <p>Here is the relevant snippet from the BLE core specification:</p> <p><em>The Client Characteristic Configuration descriptor value shall be</em><br /><em>persistent across connections for bonded devices. The Client Characteristic</em><br /><em>Configuration descriptor value shall be set to the default value at each</em><br /><em>connection with non-bonded devices.</em></p><div style="clear:both;"></div>