1. Why do we upgrade time zone from 4 to >11 while upgrading to 18.104.22.168?..What will happen if we do not update the timezone using dbms_dst package after upgrading the db?..i.e, even after upgrading the db from 10.2.0.5 to 22.214.171.124 if the timezone value remains 4.
2.What is the difference in upgrading the timezone value to 11,12,13,14 etc...what do these different values signify?..
3.In one upgrade guide I found it should be >11. My question is what should I set it to ?..12,13,14??
4.What is the concept of daylight saving time?
I could mechanically use the dbms_dst package to update the timezone to 14..but I wish to know..(and hope other people also wish) the funda behind doing so.