https://devzone.nordicsemi.com/f/nordic-q-a/63499/mesh-bootloader-accepting-dfu-with-version-lower-than-the-request-versionWe have some devices out in the field with a mixture of application versions. In one particular case, we have device A on application version 10 and we have device B on application version 20. Both devices are near each other so once device A sees deviceen-USTelligent Community 13Wed, 08 Jul 2020 11:42:06 GMThttps://devzone.nordicsemi.com/thread/258982?ContentTypeID=1Wed, 08 Jul 2020 11:42:06 GMT137ad170-7792-4731-bb38-c0d22fbe4515:4553d349-684d-4fb1-bf4d-ef2a6f1601d9tesc<p>Hi,</p> <p>Only accepting upgrades (not downgrades) is the expected default behavior.</p> [quote user=""]Or is the device expected to accept a DFU with a version lower than what it&#39;s asking for (but still higher than its current version)?[/quote] <p>I do not quite understand what you mean. The DFU target does not &quot;ask for&quot; any particular version. When the DFU source pushes out an upgrade, nodes with the DFU bootloader will check if the upgrade is for their application (checking application ID.) If application ID match and also the version is higher than the current application, it will act as DFU target (and DFU relay.) If it is a different application it will act only as DFU relay. As DFU target it will receive and accept the upgrade being pushed by the DFU source.</p> <p>Regards,<br />Terje</p><div style="clear:both;"></div>