To retrieve older Teams chat messages, you can use the search functionality within Microsoft Teams. However, if you are unable to find conversations from July and can only access chats from September, it may be due to retention policies set by your organization or limitations in the Teams interface itself.
If your organization has enabled eDiscovery, you might be able to search for older messages through that feature. You can use specific keyword queries to narrow down your search results, but the context provided does not detail the exact steps for retrieving older chats directly from the Teams interface.
If you continue to have difficulty accessing older chats, consider reaching out to your IT administrator for assistance, as they may have access to tools or settings that can help you retrieve the information you need.