(save-excursion
(let ((proc (notmuch-start-notmuch
"notmuch-search" buffer #'notmuch-search-process-sentinel
- "search" "--format=sexp" "--format-version=2"
+ "search" "--format=sexp" "--format-version=4"
(if oldest-first
"--sort=oldest-first"
"--sort=newest-first")