Yes, you need to mail your return with Form 8283 if an attached appraisal is required, sorry.
I haven't seen other users post the conflicting info you received, so have no context for this, unfortunately. Some Form 8283's can indeed be Efiled.
An option would be to Efile without Form 8283, and amend later to add it, or edit your donations to Efileable ones, and amend later for the one requiring a written appraisal and mail.
Here's more info on Form 8283.
@redhawklady
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"