The 20th anniversary invitation is an item given to all players upon logging in after the update on 14 December 2020.
It promotes the RS20 Grand Party starting on 4 January 2021, and offers free teleports to the Grand Party in Lumbridge Crater. Attempting to teleport before the party has started yields the message The party hasn't started yet. Attempting to teleport after the party has ended yields the message The party is over. You have no reason to teleport there anymore.
During the event, it can be used to teleport to Lumbridge Crater near the Wise Old Man.
You have been cordially invited to the RS20 Grand Party in Lumbridge Crater beginning the 4th January.
This information has been compiled as part of the update history project. Some updates may not be included - see here for how to help out!