I am wondering if it is possible to have the Daily Constraints in the Shifts automatically adjust themselves per Daylight Savings time, or if it is necessary to update them manually?

99% of the time it should be unnecessary to revise shift constraints for DST. A shift start time constraint of 9am 28-Feb will still be 9am 13-Mar and both will create a 9am shift start for their respective weeks. The 1% case is if the scheduling unit is in a time zone that honors DST and you have some agents in say Arizona where they do not follow DST - in that case you would have to adjust the shift constraints for those agents to account for the disparity in DST handling rules between two different geographic locations.