Shortening boolean with if statement for document version comparison
Sure. Use the Not operator.

if (!documentComparer.Equals(version, imported))
{
    changedDocument.Add(imported); 
}




To explain a little, it's bad practice to do things like this.

bool boolean = true;
if (boolean == false)
{
//...


because it's completely equivalent to saying

if (true == false)


and can be simplified down to

if (false)