F2O uses Fidelity Investments CSV files to produce OFX files. While there is a path to accommodate people who don't have past Fidelity OFX files, I have not seen anybody post about that experience.
The path to using has has been clearer for those who used PocketSense, but that is not necessary.
If you want to generate OFX for Fidelity Investment accounts, and don't find the way to do that successfully, say so.