nRF51 OTA DFU issue with nRF Connect iOS V1.7.5

nRF_log_1.8.1.txtHello Nordic Support Team,

We are trying to run the OTA DFU on the nRF51 device via the nRF Connect iOS application V1.7.5. The DFU Device is available, but once selecting the new FW image file, and starting the DFU process, we've got the following error message: "Abort ! DFU service not found". This issue is always detected on different iOs versions (V9.3.5, V10.3.2 and V10.3.3).

TODAY, we've updated the nRF Connect iOS application from V1.7.5 to V1.8.0 (released yesterday 11th October); and as a magic spell the OTA DFU is now working correctly using this updated version. But sometimes the DFU process fails even with the V1.8.0 nRF Connect version with different iOS versions. Issue is not systematic :(

We did not find within the "What's new" section of version V1.8.0 that may explain this behaviour... Any help Please ?

PS: Issue described above is not reproduced, and the DFU process is running successfully, once using: nRF Connect on Android Application V4.13.1 and nRF Toolbox iOS application V4.4.1

nRF_log.txt

BeST Regards, -Heisenberg-