Naming software and user adoption

Are there best practices or any general advice on how to name software? Here's my situation:

For many years, users have been using various access forms and reports to interact with (read/write) an access database. We are now moving to SQL server and developing a web app to replace the access forms (they cannot be maintained at this point so continued use with a SQL server data source is out of the question)

The old system has a name (let's say "x") adopted by all users. Would it be appropriate to maintain the name and add 2 (or 2.0) at the end (x 2.0)? Right now most users are referring to it as "the new x" software.

Some colleagues have suggested lengthy names that better describe the function of the database and front end but if all users are already calling it x is there any reason why I shouldn't keep the name and just make sure it's differentiated from the "old x"?

Let me know if you need additional info. Thanks!