diff --git a/README.md b/README.md
index 1e2c724..d482f63 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ are regenerated on each release — patches cannot be merged directly.
 Report problems (or send patches) to the author; accepted changes are
 applied to the development tree and appear in a following snapshot.
 
-This snapshot was assembled from development commit `ca9eaa2c867a`.
+This snapshot was assembled from development commit `43a4ce7dea2a`.
 
 ## License
 
diff --git a/doc/edit/emacs/README.md b/doc/edit/emacs/README.md
index a9ce9be..4ce6290 100644
--- a/doc/edit/emacs/README.md
+++ b/doc/edit/emacs/README.md
@@ -4,6 +4,9 @@
 helps Klammertext authors see the structure of klammer application through
 syntax highlighting.
 
+Requires **Emacs 27.1 or newer** — the version Ubuntu 22.04 and Pop!_OS
+22.04 ship, so it is the practical floor.  Tested on 27.1 and 30.2.
+
 ## Install
 
 Put the `emacs` directory somewhere on your system, then tell Emacs where it is
diff --git a/doc/edit/emacs/klammertext-align.el b/doc/edit/emacs/klammertext-align.el
index b75e13d..a9cd8aa 100644
--- a/doc/edit/emacs/klammertext-align.el
+++ b/doc/edit/emacs/klammertext-align.el
@@ -50,6 +50,11 @@
 
 ;;; Code:
 
+;; string-trim, string-blank-p, and string-empty-p live in subr-x, which is
+;; not loaded by default in a batch Emacs before 28.  Without this require
+;; they are void on Emacs 27 (as shipped by Pop!_OS 22.04) while working on
+;; newer Emacs, so the alignment command fails on the older editor only.
+(require 'subr-x)
 (require 'klammertext-mode)
 
 (defgroup klammertext-align nil