Working on the upgrade from 1.9.5 to 4.7.1 and noticed the columns are different when the DATABASECHANGELOG table is updated versus created. We run a table structure comparison to ensure our application tables are consistent and these showed up as differences. This is on MSSQL, btw.
Column Updated Created
----------- ------------ -----------
AUTHOR varchar(63) varchar(255)
DATEEXECUTED datetime datetime2
FILENAME varchar(200) varchar(255)
ID varchar(63) varchar(255)
Also the DATABASECHANGELOGLOCK.LOCKGRANTED is datetime
vs datetime2
.