Redmine

We need clarity on how multiple changes made by an user to a set of custom fields in a task tracker is recorded in the database.

1) Is this user based?

2) If so, how is the user based history of changes recorded in Redmine database? Does it capture every custom field changes that is made by the user or only the last change? Need clarity on the logic.

Currently, we find only the last entry of changes to be captured in our database.

Thanks in Advance!