Just got my ZT-703S yesterday. It came with 1.32 and I immediately updated to 1.39. Auto range just doesn't seem to work at all on 1.39. It takes forever and just ends up on minimum time and 100V scales, so completely useless. When in AC mode it sometimes seems to work, but inconsistently.
I reverted to 1.32 and at least in the range I've been testing up to 1MHz, the auto-range captures the waveform and comes in ballpark range.
So, I'll be sticking with 1.32 for now. I think all the tweaking they have been doing in the latest firmware to get rid of the jitter in the high frequency range, may be affecting the auto-range? But that's just my ignorant guess.
Anyway, anyone interested in Auto-Range should try 1.32.