====== Change Matrix room retention time ======

Systemli's Matrix home server instance has a default retention time of 30 days. We allow values from 1-180 days. 

<note important>Clients that have already downloaded and stored the event/message might continue to show it, unless they themselves implement support for message retention policies, the homeserver can not do anything about this.</note>

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It is possible to send custom events from developer tools of element web and set room retention time there.
  - The developer tools can be opened by typing ''/devtools'' in the message editor.
  - In the devtools, select "Explore room state"
  - If the retention has not previously set, `m.room.retention` will not show up in the overview
  - Click "Send custom state event" 
    - You'll first need to convert the desired time in days to milliseconds, i.e.: 1000*60*60*24*<number_of_days>
    - Event Type: <code>m.room.retention</code>
    - Event Content: <code>
{
    "max_lifetime": 2592000000
}</code>
    - State Key: leave this empty
    - Click "Send"

After sending, you can verify that the retention is set: Go back and choose "Explore room state". Now ''m.room.retention'' should show up in the overview. 

----

Source: https://github.com/vector-im/element-web/issues/3800#issuecomment-1030568445

===== Further reading =====

  * [[https://github.com/matrix-org/synapse/blob/develop/docs/message_retention_policies.md#room-configuration|Matrix Message retention policies]]
  * [[https://spec.matrix.org/latest/|Matrix Client API documentation]]