Compatibility issues between FastReport VCL and FastReport 4/5/6:

- FastReport VCL uses the same file/package names as v4/v5/v6. You have to uninstall v4/v5/v6 before 
installing FastReport VCL.

- FastReport VCL uses the same file format, .fr3 and can open v4/v5/v6 files without any problems.

- FastReport VCL can read v4/v5/v6 .fp3 files.