Under docs.bmc.com, if you search for Track-It! 2020, you will find a section in there about upgrading/migrating and it should point out the specific version of 11.4 you need. This will be the same for 2019 or 2020.
We do not offer webex migration assistance. If you would like that type of service, there are several Track-It! consultants available for hire that we could recommend.