Is it possible do a DFU to switch between SDK versions?

[Mufasa1]

Hi all,

I am experimenting with the DFU to switch between SDK versions from SDK12 to SDK13 and SDK13 to SDK12

Is it possible if I send a whole imagen of SD+BL+APP to switch between SD12+BL12+app12 and SD13+BL13+app13, and viseversa?

Thanks

[endnode]

If you mean "can I switch by using OTA DFU mechanism from BLE APP compiled with one SDK version to another BLE APP compiled with different SDK version" then the general answer is YES. However I guess Nordic don't guarantee compatibility of their Bootloader and DFU examples between all possible SDK versions so all combinations you want to support in your application should be always tested prior to release (what I mean is: if you have devices in the field compiled with SDK X and you migrate to SDK Y then you test DFU between these two versions. If you continue in development and migrate to SDK Z then you should test both DFU paths, from X to Z and from Y to Z. And so on if you continue in migrations. If you also support "downgrades" aka opposite paths then your testing effort doubles.)