To save on the 6 hours update time from a fresh install I've made a new full update package
This is assuming you have installed from the latest official installer from Square Enix that can be found here:
http://www.playonline.com/ff11us/download/media/install_win.html
* http://gdl.square-enix.com/ffxi/download/us/FFXISETUP.exe
* http://gdl.square-enix.com/ffxi/download/us/FINALFANTASYXI.Data.001
* http://gdl.square-enix.com/ffxi/download/us/FINALFANTASYXI.Data.002
* http://gdl.square-enix.com/ffxi/download/us/FINALFANTASYXI.Data.003
Update up to 2018-08-09:
https://drive.google.com/open?id=1jVwflKOw2VwWfPRKkmUe_b8hiAp_aCeU
This is using High efficient compression to keep the otherwise >4GB update down to a mere <900MB
https://drive.google.com/open?id=1gaiI8CSH9taJmXcmsta32H6KFqxVRfkC
This is in a simple .zip file at around 1.5GB
I am currently working on integrating the update into the install files to save even more time.
Enjoy
--- edit ---
Please see Kireek's post on page 2
The new installer Square just released is up-to date with current files, so when you install the game from that there will be no update.
It's the best and fastest way to install ffxi right now.