Example: If I have multiple years of historical changes to a ticket, will Ketryx capture that history and make it available for view in Ketryx? 

No. For historical changes that have been made prior to connecting your Jira project with Ketryx, the product does not provide you with a line-by-line version history for those changes. The Ketryx Platform begins logging changes on the record details page starting at the time of connection.