Restrictions are listed in the patch notes.
Restrictions
Certain features are unavailable or restricted when visiting another World.
Disciples of the Land
Legendary and unspoiled gathering nodes are inaccessible.
Retainers
Retainers cannot be summoned, hired, or released from service.
Items cannot be put up for sale on the market board.
* Market board items can still be purchased.
The following quests can only be accepted from your Home World:
An Ill-conceived Venture (Gridania, Limsa Lominsa, Ul'dah)
Free Companies
Free companies cannot be formed or joined.
Free company information cannot be viewed.
* Login status of free company members will be displayed in the chat log as usual.
Company credits cannot be earned.
Linkshells
Linkshells cannot be used to send or receive messages.
Linkshell information cannot be viewed.
Linkshells cannot be created or joined.
Housing
Estates and apartments cannot be purchased.
Residence sharing is unavailable.
The following quests can only be accepted from your Home World:
Bird in Hand
Eternal Bonding
Ceremonies of Eternal Bonding are unavailable.
Eternal Bonding quests are unavailable.
Others' ceremonies cannot be attended.
Gold Saucer
Lord of Verminion tournaments cannot be entered.
Triple Triad tournaments cannot be entered.
Cactpot tickets cannot be purchased.
Deep Dungeons
Deep Dungeon results will not be saved to leaderboards.
Moogle Delivery Service
The Moogle Delivery Service is unavailable, but you will receive a notification when logging in to the World that you are visiting when a letter has arrived.
* Notifications for letters from GMs will be displayed instantaneously, not only when logging in.
* All notifications received when visiting another World will be indicated with the red letter icon.
Teleport
Eternity Rings may only be used when both players are on the same World.
You can only use an Aetheryte Pendulum to teleport to the nearest aetheryte if both players are on the same World.
You can only teleport to a friend's estate when you are on their Home World.
* This feature may still be used even when your friend is visiting another World.
New World and Preferred World Bonuses
Bonuses will not be applied for visiting New Worlds or Preferred Worlds.
* If you are eligible for New World or Preferred World bonuses in your Home World, these will still apply when visiting another World.