Past messages in group chat

Good morning, we would like our users to see past messages posted BEFORE joining the channel, we’re not sure how to accomplish this.
We managed to use an api token to retrieve all messages in a channel but this might be because the user authenticates me as an administrator/moderator.
We found out that probably the call sent by the SDK is similar to

curl -H "Host: api-foobar.sendbird.com" -H "accept: application/json" -H "session-key: foobar" -H "sendbird: iOS,15.2,3.1.3,FOOBAR" -H "request-sent-timestamp: 1645618554123" -H "user-agent: Jios/3.1.3" -H "sb-user-agent: iOS/c3.1.3" -H "accept-language: en-GB,en;q=0.9" --compressed "https://api-foobar.sendbird.com/v3/group_channels/sendbird_group_channel_foobar/messages?prev_limit=40&with_sorted_meta_array=true&reverse=false&show_subchannel_messages_only=false&message_ts=1645618554123&include_thread_info=false&include_reply_type=none&is_sdk=true&include=false&include_parent_message_info=false&next_limit=0&include_poll_details=false&custom_types=%2A&include_reactions=false"

But we can’t figure out how to change it to accomplish what we want. That channel should have a couple messages posted a few minutes before my user joined, we tried to change the “message_ts” but for some reason the query comes back empty.
Do you have any suggestion?

Hi @ngw and welcome to the Sendbird community.

You will have to turn on “Chat history” from App Settings > Chat > Channels > Group channels > Chat history: