What a row tells you

Your devices is the list of everything that can open this vault. Each row is one device: an icon for what it is, the name it goes by, and a small line under it with the rest.

Devices

Add another device with a QR, or remove one.

Settings › Sync and account › Devices: button: Manage.

The Your devices list with three rows. Each row has a platform icon, a device name, and a line under it giving the platform, when it was last seen syncing, and the app version. The first row is marked This device. The third row carries a small chip that reads outdated. Each row has a pencil to rename and a bin to remove, except the row for the device you are on, which has no bin. Three devices on one vault. The row you are sitting on says This device and cannot be removed from here.

This device marks the one you are looking at. It is always first in the line.
The platform says what it is: windows, macos, linux, android or ios.
When it was last seen is the last time that device synced, written as seen just now or seen 3d ago. A device that has been off for a while is not a problem, it is just quiet.
The version is the build of Relic it reported. The one you are on reports live; the others can be up to an hour behind.
An outdated chip appears when a device runs an older build than the one you are on. Hover it and it says which version each is running, and to update from relic.space/download. Sync still works across versions.

Rename or remove a device

Open the list
On a computer open Settings›Sync and account›Devices and press Manage. On a phone, open the settings sheet and tap Your devices. The screen is called Your devices and it lists everything signed in to this vault.
Rename one
Click a row, or the pencil at its right, and Rename device opens with the current name in a Device name field. Type a better one and press Save. The new name shows up on your other devices at their next sync, and on every item that device captures from then on.
Remove one
Press the bin at the right of the row. Relic asks Remove device? and names the one you picked: Remove "Pixel 9"? It will lose access to your vault on its next sync. Press Remove. The row you are sitting on has no bin, so you cannot remove the device in your hands.
Sign back in where you want to keep syncing
Removing signs every device out of the account, including yours. Sign in again on each device you kept and sync carries on where it left off. Nothing in any vault is touched. See below for why.

What removing does

The removed device loses access to your vault on its next sync. It keeps whatever it had already downloaded, because that copy lives on its own disk, but it cannot pull anything new and it cannot push.

Removing also signs every device on the account out, yours included. That is the only way to make the removal stick straight away: a device that is still signed in could otherwise carry on for up to an hour on the session it already has. Each device you kept shows a banner and waits for you:

You were signed out. Sign in again to resume syncing. Your vault is safe on this device.Sign in

Your vault, your recovery kit and your items are untouched by any of this. The same thing happens when you use Sign out everywhere in Security, which is what to reach for when a device is lost rather than retired.

A confirm dialog titled Remove device? Its body reads: Remove Pixel 9? It will lose access to your vault on its next sync. A Cancel link sits beside a red Remove button.

The device limit

A plan allows a set number of devices, and larger plans allow more. When a new device tries to join a full account, Relic stops it with a dialog headed Device limit reached:

Your plan is full. Remove a device to connect this one, or upgrade your plan for more devices.

Under that sits the same list of devices, each with a Remove button. Remove one and the new device joins straight away, so you do not have to go back and start over. Not now closes the dialog and leaves the new device unconnected. It can still capture and search on its own.