When converting older database versions (13,14,15) to v16, there are a few differences to be aware of when concerning the data file. Below is a table that summarizes what happens to the data file based of the version the database is converting from.

Original version	Converted to 16	Versions data file can be opened in after conversion
13	Data file converted.	14, 15, 16
14	Date file converted.	14, 15, 16
15	Data file opened. No conversion.	14, 15, 16

Note: If converting from 13 to 16, the data file will no longer be able to be opened in 13.

For more information about converting to 16, see documentation here.