Admins choose whether new members get full history or only messages from the day they join. It's set per invite, not per chat.
When you invite someone to a chat in Pigeon, you choose what they can see: Full history from the start of the chat, or only messages from the time they join going forward. This is set individually at the moment they are invited.
To invite new members to a chat, you need to start a chat or be an admin within an existing chat.
To learn more about what admins can do, see How do admin controls work in Pigeon?
Full history — the new member can see everything sent in the chat from the very first message. Use this for chat members who need full history for context about what was said before they joined.
From join date — the new member can only see messages sent after they joined. All messages sent before they joined are not visible. Use this for chat members who shouldn't have access to previous messages but are now needed as part of the chat.
Team members come and go and this ability gives you the option to choose what to share to new members of your chats. Whether it's a new client joining an existing project chat or a new team member joining your internal chat, you get to choose every time.