Posted by If you are a regular user of LOB’s in the database, take care when you switch from 11g to 12c. Notice the subtle difference:
In 11g, you are permitted to, and recommended to, use SECUREFILE lobs, but they are not the default
SQL> select name, value
2 from v$parameter
3 where name = 'db_securefile';
NAME VALUE
---------------------------------------- ---------------
db_securefile PERMITTED
In12c, SECUREFILE lobs will be the default.
SQL> select name, value
2 from v$parameter
3 where name = 'db_securefile';
NAME VALUE
---------------------------------------- ---------------
db_securefile PREFERRED
This change should be beneficial, because SECUREFILE lobs are the newer and more functional implementation, but just be aware that the default has changed between versions.
Learning is not a spectator sport 
Let’s hope the old format is stll fully supported, otherwise upgrading to 12c is going to be a nightmare for a lot of folks…
Lazy question:
Will it be possible to have a partitioned table where the old partitions were using Basicfiles and the new partitions can use securefiles ?
A blog post to come …. an interesting result found
Well the syntax certainly is supported.
Will let you know if I hit some 600s though 🙂