I'm in the same boat!
Muntasir Sakib:
1 - Whenever you override anything, you won't get new features of that from the next updates.
This is lie. your update just broke everything. all my overrides are rewiritten.
2 - Though I have answered it already, this is the folder where all the overriden files are placed. All the new updates will be changed inside this folder accordingly with every next update. However, if you override anything on your own, only that file won't affect the update as template > shaper_helixultimate > html has higher priority.
Lie again, when template got updated, overrides were ALSO REWRITTEN
so, none of EXPECTED AND PRE-PLANNED AND PREASSIGNED SPECIFICALLY FOR OVERRIDES folders are kept intact while your updates.
Do you even TEST your updates???