Hi

The current org latex export will export a link doi:10.xyz/abcd without
the protocol prefix as 10.xyz/abcd. Correctly, it should retain the
prefix.

An easy fix is adding "doi" to the list of protocols that retain
the link type string in ox-latex.el, below.

################### ox-latex.el ###############
(defun org-latex-link (link desc info)
  "Transcode a LINK object from Org to LaTeX.

DESC is the description part of the link, or the empty string.
INFO is a plist holding contextual information.  See
`org-export-data'."
  (let* ((type (org-element-property :type link))
 (raw-path (replace-regexp-in-string
    "%" "\\%" (org-element-property :path link) nil t))
 ;; Ensure DESC really exists, or set it to nil.
 (desc (and (not (string= desc "")) desc))
 (imagep (org-export-inline-image-p
  link org-latex-inline-image-rules))
 (path (cond
                ;; ----- NEXT LINE CONTAINS THE FIX -------
((member type '("http" "https" "ftp" "mailto" "doi"))
 (concat type ":" raw-path))
((and (string= type "file") (file-name-absolute-p raw-path))
 (concat "file:" raw-path))
(t raw-path)))
 protocol)
#############

Best regards,
Derek