I have a property in a class that is a sequence of items, like:

private LinkedList<T?> valueHistory = new ();

public IEnumerable<T?> ValueHistory
{
    get => valueHistory; 
}

public T? CurrentValue
{
    get => valueHistory.LastOrDefault();
    set => valueHistory.AddLast(value);
}

This works, but I want to communicate to a consumer that the value history is in sequence, which (if I understand correctly) I don’t think IEnumerable does?
And I want to be free to change the backing field from a LinkedList to a List, or an array, or anything else that makes more sense later.

What type do I declare ValueHistory as to indicate that the consumer can rely on the sequence of values being correct?