In sestosenso2.cpp I changed line 1552, to the following
1550 bool CommandSet::getAbsolutePosition(char *res)
1551 {
1552 return sendCmd("{\"req\":{\"get\":{\"MOT1\":{\"ABS_POS\":\"\"}}}}", "ABS_POS", res);
1553 }

Similarly on line 1557
1555 bool CommandSet::getCurrentSpeed(char *res)
1556 {
1557 return sendCmd("{\"req\":{\"get\":{\"MOT1\":{\"SPEED\":\"\"}}}}", "SPEED", res);
1558 }

While debugging I also noticed that the focusser response was truncated when requesting the NTC temperature.
Although the NTC_T property was not in the truncated part and the function worked, I changed line 1649 too:
1647 bool CommandSet::getMotorTemp(char *res)
1648 {
1649 return sendCmd("{\"req\":{\"get\":{\"MOT1\":{\"NTC_T\":\"\"}}}}", "NTC_T", res);
1650 }

There might me more routines with the same problem but I haven't noticed them. I don't know whether
older firmware has a problem with these changes.