I recently bought the newer version of this power bank from Ebay and I’m did some tests.
The old version has a cut-off voltage of 4.19-4.22. I owned three. New version has a cut-off voltage of ~ 4.31-4.34V. Discharge cut-off is ~3.07V. The tests has been done both with high internal resistance batteries(4.34V) and with new, good quality batteries (4.31-4.32V). Interesting, resting voltage immediately after cut-off is 4.29V in both cases. It seems that interrupts the charging current from time to time to check the voltage. To conclude, dangerous for the 4.2V batteries, good for the new 4.35V batteries. I’m curios if that is consistent with all these new power banks or only my version cut-off at 4.32V incidentally.