2 files changed, 4 insertions, 1 deletions

diff --git a/etc/NEWS b/etc/NEWS
index c69bbe9d0f6..2a93bdf0253 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -713,7 +713,8 @@ manual for more details.
 +++
 ** New function 'proper-list-p'.
 Given a proper list as argument, this predicate returns its length;
-otherwise, it returns nil.
+otherwise, it returns nil.  'format-proper-list-p' is now an obsolete
+alias for the new function.
 
 ** define-minor-mode automatically documents the meaning of ARG
 
diff --git a/lisp/format.el b/lisp/format.el
index 5bf1be39475..49d3c718abc 100644
--- a/lisp/format.el
+++ b/lisp/format.el
@@ -539,6 +539,8 @@ Compare using `equal'."
         (setq tail next)))
     (cons acopy bcopy)))
 
+(define-obsolete-function-alias 'format-proper-list-p 'proper-list-p "27.1")
+
 (defun format-reorder (items order)
   "Arrange ITEMS to follow partial ORDER.
 Elements of ITEMS equal to elements of ORDER will be rearranged