MENDIX 4.5.2 Upgrade - ORACLE

This is a follow-up to my previous question : In the upgrade script, the indexes get dropped, the primary keys get dropped, the ID field gets changed to Number(20), the value of the ID gets updated by adding a value, and then the indexes and primary keys get added again. Nowhere does the sequences get updated or removed. Does the sequences still get used in Mendix 4? I also don't understand the reason for updating the actual data, if anyone can clarify this for me, it would be greatly appreciated.
1 answers

1) Yes sequences are still used in Mendix 4.

2) The data is being updated because identifiers are now 64 bits of which the first 16 bits are made of an entity identifier, meaning every id already contains information on what entity it is. The remaining 48 bits are an upgrade from the 32 bit identifiers in Mendix 3 where we had at least 1 customer where the data had to be archived because they simply had too many objects in a table.

How this technically works I also explained at