After updating to this version also no strength indication on the gsm signal bar, don't know about 4G, don't have....
Someone claimed it's a transparency bug, i don't think so, i did saw an output strength appearing for a brief moment.
Tested signal with Network Signal Info app and it showed a -113dBm signal, so no signal at all.
Making and receiving calls is possible, however, sometimes it takes a while setting up the connection...
I tried to flash an older version but ended up with android error messages after the older rom was installed.
(yes i cleared cache/dalvik cache)
So reluctantly installed the 6.1.7 again...... :-/
Redmi Note 2 TD