This question is commonly asked, but the answer will always differ as a database can vary in complexity. Here are things to consider before moving to a newer version:
1. Confirm whether OS will be supported in the newer version of 4D in the link below:
2. Contact account rep to request a free conversion report.
3. Based on the report, decide whether the conversion will be done by yourself or 4D's Professional Services.
Moreover, it can be worthwhile to create a copy of the current database and open that copy in the newer version of 4D to see what works and what doesn't. Typically the larger the jump between versions, the higher the chance more work will need to be done to get things working in the new version.