https://devzone.nordicsemi.com/f/nordic-q-a/73341/smp-pairing-behaviour-change-in-sdk-1-5-0I have recently updated from SDK 1.4.2 to 1.5.0 on an nRF5340-DK I have an application with a custom ble service. Most of the services have authentication permission requirements on them (e.g. BT_GATT_PERM_READ_AUTHEN), meaning they can only be readen-USTelligent Community 13Mon, 29 Mar 2021 14:09:48 GMThttps://devzone.nordicsemi.com/thread/302404?ContentTypeID=1Mon, 29 Mar 2021 14:09:48 GMT137ad170-7792-4731-bb38-c0d22fbe4515:71dfaa31-de3e-4d4f-ad40-da2f36e8185dSimon<p>I&#39;m happy you made it work and thanks for telling me that you figured it out.</p> <p>Best regards,</p> <p>Simon</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/302402?ContentTypeID=1Mon, 29 Mar 2021 14:03:32 GMT137ad170-7792-4731-bb38-c0d22fbe4515:895c968a-411b-45fe-8612-c522aeae8bced_c_h_w<p>HI, sorry this is not a 1.4.2 vs 1.5.0 issue as I have now got it working on v.1.5.0 also</p> <p>My issue was due to using CONFIG_BT_SETTINGS where the SMP pairing info is stored persistently.&nbsp;</p> <p>If I &#39;forget&#39; the device on my iphone and still have the pairing info on the peripheral then when it connects it attempts the smp security exchange, as it thinks both sides have the necessary pairing info.</p> <p>When I tried to reproduce it with 1.4.2 I did a flash erase which removed any persistent storage and that it why it worked.</p> <p>So this is not a real issue, just an inconvenience that happens if one side and not the other removes their pairing info.</p><div style="clear:both;"></div>