diff --git a/technical/2.3.-Swarm.md b/technical/2.3.-Swarm.md
index 13b6f0c4..34b195a2 100644
--- a/technical/2.3.-Swarm.md
+++ b/technical/2.3.-Swarm.md
@@ -242,6 +242,17 @@ END:VCARD
 
 To update the vCard, a user with enough permissions (by default: =ADMIN) needs to edit `/profile.vcf`. and will commit the file with the mimetype `application/update-profile`. The new message is sent via the same mechanism and all peers will receive the **MessageReceived** signal from the daemon. The branch is dropped if the commit contains other files or too big or if done by a non-authorized member (by default: <ADMIN).
 
+#### Last Displayed
+
+In the synchronized data, each devices sends to other devices the state of the conversations. In this state, the last displayed is sent. However, because each device can have its own state for each conversation, and probably without the same last commit at some point, there is several scenarios to take into account:
+
+5 scenarios are supported:
++ if the last displayed sent by other devices is the same as the current one, there is nothing to do.
++ if there is no last displayed for the current device, the remote displayed message is used.
++ if the remote last displayed is not present in the repo, it means that the commit will be fetched later, so cache the result
++ if the remote is already fetched, we check that the local last displayed is before in the history to replace it
++ Finally if a message is announced from the same author, it means that we need to update the last displayed.
+
 ### Merge conflicts management
 
 Because two admins can change the description at the same time, a merge conflict can occur on `profile.vcf`. In this case, the commit with the higher hash (eg ffffff > 000000) will be chosen.