Call Disconnects on Yealink T26P

[Yealink Support]

Hello Yogi,
1.Because now you are still use V61, so the auto provisioning file format is the same as before, you just need to change the firmware name in the cfg file, the the phone will upgrade to the new V70 firmware.
2.But after you upgrade to V70, you can't use previous cfg file, because V70 cfg file format is different(called M7), you should use M7(V70 cfg file), you can find the template from our website.
3.You said you upgrade failed, could you send me your cfg file, so i can check at my side.