The channel menu: what you can do with a connected channel

Each connected channel on the Dashboard has a ⋮ More actions button. It holds everything you can do to that one channel, so there is no separate settings icon next to it.

Action	What it does
Refresh connection	Signs in to the platform again to renew an expired or revoked connection. Use it when a channel says Reconnect needed. See Login health and reconnecting.
Channel settings	Opens that channel's page in Settings → Security, where you can see its connection details.
Brand voice	Shown where the feature is available. Teaches the AI how this channel writes. See Brand voice.
Backfill history	Reads this channel's older posts from the platform into Sent and Insights. See below.
Disconnect channel	Removes the connection. Postalu's own posts stay; the stored copy of the channel's posts is removed. See Disconnect an account.

1. Backfill history

Where Sent is switched on, Postalu reads each channel's newest posts automatically. Backfill history goes further back, up to 12 months and 500 posts at a time, and picks up where the last run stopped, so you can run it again to read further back.

A message tells you how many older posts were read and whether the channel is now fully up to date.
You need permission to manage that platform, and it can be run a few times an hour per person.
X is different: every read on X is billed, so Backfill is manual only and reads at most 100 posts a time, twice an hour.
LinkedIn personal profiles cannot be read at all, because LinkedIn does not allow it; the action says so.
A channel that needs reconnecting must be reconnected first.