From FlyFF WIki
Patches are made available for download following maintenance.
Maintenance is Tuesdays from 8am to 10am GMT unless otherwise posted.
Normally there are no manual patches available unless otherwise posted by a CM or MOD on the official forums. This applies to both the game and GameGuard. The number of patches required by the game client varies depending on the last time the game client was patched. Normally users only need to download the latest patches from the patch server. New installations will require all the patches to be downloaded. All patches are automatically downloaded by the patcher. GameGuard patches are download by Neuz when the start button is pressed on the game client. It is possible to have patches for the game and not GameGuard. It is necessary to patch before playing to avoid unnecessary crashes.
Please see Patch History for details of prior patches.