https://devzone.nordicsemi.com/f/nordic-q-a/26402/application-with-dfu-in-13-0-0-1Hello, I realized that different SDK versions have different behavior for DFU. I&#39;d like to add DFU feature into my heart rate application. In nordic infocenter, it&#39;s mentioned that &quot;If a valid application is installed on the device, hold Button 4 duringen-USTelligent Community 13Tue, 31 Oct 2017 22:58:27 GMThttps://devzone.nordicsemi.com/thread/103905?ContentTypeID=1Tue, 31 Oct 2017 22:58:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e2a8c739-8c8e-42d5-ab64-b5270895515dbjorn-spockeli<p>Great :) I would appreciate if you could mark the answer as accepted/correct by clicking the check mark in the grey circle to the left of the answer.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/103904?ContentTypeID=1Tue, 31 Oct 2017 09:51:33 GMT137ad170-7792-4731-bb38-c0d22fbe4515:34705084-7606-417c-abda-55d0dedb9d73Mich<p>Thanks! It works</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/103903?ContentTypeID=1Sun, 29 Oct 2017 16:33:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:8650aaee-002f-4fdf-835e-d50f99f42d78bjorn-spockeli<p>Hi Mich,</p> <p>see Appendix 1 in the <a href="https://devzone.nordicsemi.com/blogs/1085/getting-started-with-nordics-secure-dfu-bootloader/">Getting started with Nordic&#39;s Secure DFU bootloader</a> blog post.</p> <p>Best regards</p> <p>Bjørn</p><div style="clear:both;"></div>