Hello, if the group admin turn on the [Chat Rrcords] selection, new member can check the last 100 messages record.：

Setting path：
1、Mobile DingTalk：[Group chat page] -The portrait in the top right corner [Group Settings] - [Group Management] - [Chat Records]；
2. Desktop client：[Group chat page] - The portrait in the top right corner [Group Settings] - [Manage Group] - [View Chat History].