One consequence of this was seen in the first proposed fix for
DERBY-5274. When using the CHAR function to convert a BIGINT in SYS.SYSCOLUMNS to a CHAR value in DatabaseMetaData.getColumns(), a truncation error was raised when running on a database upgraded from 10.3.1.4 or earlier.
For a simple reproduction, create a database with 10.3.1.4 and boot it with 10.8.1.2. Then execute the following statements:
ij> create table t (x int not null generated always as identity (start with 12));
0 rows inserted/updated/deleted
ij> select char(autoincrementstart) from sys.syscolumns where columnname='X';
ERROR 22001: A truncation error was encountered trying to shrink CHAR '12' to length 1.
If the database had been created with 10.4.1.3 or later, the select statement would complete successfully.