How to manage communications so that you never lose track of any request ?

When developping a solution using an Agile methodology, it is common to receive requests from the customer during a Sprint.

In principle, it has been clarified since the beginning of the project that requests not having been planned upstream cannot be added to an ongoing Sprint.

Anyway, not taking care of a request immediately does not mean that it can be forgotten : after a few weeks, at best, one remembers vaguely that someone had talked about something, without being able to specify when or via which channel.

However, not losing track of customer requests is fundamental to ensure the continuous deployment strategy of a solution.