Which version of SwissSys do I need?

The regular (full) registration of SwissSys supports tournaments run using guidelines from both the US Chess Federation and FIDE, the international chess body.The FIDE-only registration is identical in every way to the full registration except that running in FIDE mode is the only option and some USCF functions are locked out, such as the USCF pairing engine and the USCF rating report utility.

In general, if you plan to run events in the U.S., you will need the full registration If not, you might want to take advantage of the low-cost introductory price offered to FIDE arbiters.

If you buy the FIDE-only registration and later decide to upgrade to the full registration, you will only need to pay the difference in price between the two.