es gibt Datumsmathematik: (#define USE_FEXTRACT)
cts(tstamp flg) convert timestamp to German locale format back and forth flg=0 to webformat, 1 to German format
tso(tstamp day flag) add time offset in days to timestamp optional flg = char 0 zo zero time HH:MM:SS
tsn(tstamp) convert timestamp to seconds
s2t(seconds) convert seconds to Tasmota timestamp