diff --git a/libguile/init.c b/libguile/init.c
index 408e15334..38712b647 100644
--- a/libguile/init.c
+++ b/libguile/init.c
@@ -444,7 +444,7 @@ scm_i_init_guile (struct gc_stack_addr base)
   scm_init_read ();
   scm_init_strorder ();
   scm_init_srfi_13 ();
-  scm_init_srfi_14 ();  /* Requires smob_prehistory */
+  scm_boot_srfi_14 ();  /* Requires smob_prehistory */
   scm_init_exceptions ();
   scm_init_throw ();    /* Requires smob_prehistory */
   scm_init_version ();
diff --git a/libguile/srfi-14.c b/libguile/srfi-14.c
index 7b11bc9f4..f38e305a9 100644
--- a/libguile/srfi-14.c
+++ b/libguile/srfi-14.c
@@ -29,6 +29,7 @@
 #include "bytevectors-internal.h"
 #include "chars.h"
 #include "eval.h"
+#include "extensions.h"
 #include "gsubr.h"
 #include "list.h"
 #include "modules.h"
@@ -40,6 +41,7 @@
 #include "strings.h"
 #include "symbols.h"
 #include "values.h"
+#include "version.h"
 
 #include "srfi-14.h"
 
@@ -1971,35 +1973,11 @@ SCM_DEFINE (scm_char_set_diff_plus_intersection_x,
 
 
 
-/* Standard character sets.  */
-
-SCM scm_char_set_lower_case;
-SCM scm_char_set_upper_case;
-SCM scm_char_set_title_case;
-SCM scm_char_set_letter;
-SCM scm_char_set_digit;
-SCM scm_char_set_letter_and_digit;
-SCM scm_char_set_graphic;
-SCM scm_char_set_printing;
-SCM scm_char_set_whitespace;
-SCM scm_char_set_iso_control;
-SCM scm_char_set_punctuation;
-SCM scm_char_set_symbol;
-SCM scm_char_set_hex_digit;
-SCM scm_char_set_blank;
-SCM scm_char_set_ascii;
-SCM scm_char_set_empty;
-SCM scm_char_set_designated;
-SCM scm_char_set_full;
-
-
 /* Create an empty character set and return it after binding it to NAME.  */
 static inline SCM
-define_charset (const char *name, size_t len, const scm_t_char_range *ranges)
+define_charset (size_t len, const scm_t_char_range *ranges)
 {
-  SCM cs = scm_from_charset (make_static_charset (len, ranges));
-  scm_c_define (name, cs);
-  return cs;
+  return scm_from_charset (make_static_charset (len, ranges));
 }
 
 SCM_DEFINE (scm_sys_char_set_dump, "%char-set-dump", 1, 0, 0, (SCM charset), 
@@ -2058,11 +2036,45 @@ SCM_DEFINE (scm_sys_char_set_dump, "%char-set-dump", 1, 0, 0, (SCM charset),
 
 
 
-#define DEFINE_CHARSET(name, stem) \
-  define_charset ("char-set:" name, cs_##stem##_len, cs_##stem##_ranges)
+#define DECLARE_C_CHARSET(name, stem) \
+  SCM scm_char_set_##stem;
+#define DEFINE_C_CHARSET(name, stem) \
+  scm_char_set_##stem = define_charset (cs_##stem##_len, cs_##stem##_ranges);
+#define DEFINE_SCM_CHARSET(name, stem) \
+  scm_c_define ("char-set:" name, scm_char_set_##stem);
+
+#define FOR_EACH_STANDARD_CHARSET(M) \
+  M ("upper-case", upper_case) \
+  M ("lower-case", lower_case) \
+  M ("title-case", title_case) \
+  M ("letter", letter) \
+  M ("digit", digit) \
+  M ("letter+digit", letter_and_digit) \
+  M ("graphic", graphic) \
+  M ("printing", printing) \
+  M ("whitespace", whitespace) \
+  M ("iso-control", iso_control) \
+  M ("punctuation", punctuation) \
+  M ("symbol", symbol) \
+  M ("hex-digit", hex_digit) \
+  M ("blank", blank) \
+  M ("ascii", ascii) \
+  M ("empty", empty) \
+  M ("designated", designated) \
+  M ("full", full)
+
+FOR_EACH_STANDARD_CHARSET(DECLARE_C_CHARSET)
+
+static void
+scm_init_srfi_14 (void)
+{
+  FOR_EACH_STANDARD_CHARSET (DEFINE_SCM_CHARSET);
+
+#include "srfi-14.x"
+}
 
 void
-scm_init_srfi_14 (void)
+scm_boot_srfi_14 (void)
 {
   empty_charset_ranges =
     scm_i_make_typed_bytevector (0, SCM_ARRAY_ELEMENT_TYPE_U32);
@@ -2070,27 +2082,12 @@ scm_init_srfi_14 (void)
   scm_tc16_charset_cursor = scm_make_smob_type ("char-set-cursor", 0);
   scm_set_smob_print (scm_tc16_charset_cursor, charset_cursor_print);
 
-  scm_char_set_upper_case = DEFINE_CHARSET ("upper-case", upper_case);
-  scm_char_set_lower_case = DEFINE_CHARSET ("lower-case", lower_case);
-  scm_char_set_title_case = DEFINE_CHARSET ("title-case", title_case);
-  scm_char_set_letter = DEFINE_CHARSET ("letter", letter);
-  scm_char_set_digit = DEFINE_CHARSET ("digit", digit);
-  scm_char_set_letter_and_digit = DEFINE_CHARSET ("letter+digit",
-                                                  letter_plus_digit);
-  scm_char_set_graphic = DEFINE_CHARSET ("graphic", graphic);
-  scm_char_set_printing = DEFINE_CHARSET ("printing", printing);
-  scm_char_set_whitespace = DEFINE_CHARSET ("whitespace", whitespace);
-  scm_char_set_iso_control = DEFINE_CHARSET ("iso-control", iso_control);
-  scm_char_set_punctuation = DEFINE_CHARSET ("punctuation", punctuation);
-  scm_char_set_symbol = DEFINE_CHARSET ("symbol", symbol);
-  scm_char_set_hex_digit = DEFINE_CHARSET ("hex-digit", hex_digit);
-  scm_char_set_blank = DEFINE_CHARSET ("blank", blank);
-  scm_char_set_ascii = DEFINE_CHARSET ("ascii", ascii);
-  scm_char_set_empty = DEFINE_CHARSET ("empty", empty);
-  scm_char_set_designated = DEFINE_CHARSET ("designated", designated);
-  scm_char_set_full = DEFINE_CHARSET ("full", full);
+  FOR_EACH_STANDARD_CHARSET (DEFINE_C_CHARSET);
 
-#include "srfi-14.x"
+  scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
+                            "scm_init_srfi_14",
+			    (scm_t_extension_init_func) scm_init_srfi_14,
+			    NULL);
 }
 
 /* End of srfi-14.c.  */
diff --git a/libguile/srfi-14.h b/libguile/srfi-14.h
index c3cb8f427..2cc5aa8f5 100644
--- a/libguile/srfi-14.h
+++ b/libguile/srfi-14.h
@@ -101,6 +101,6 @@ SCM_API SCM scm_char_set_full;
 SCM_INTERNAL int scm_i_char_sets_equal (SCM a, SCM b);
 SCM_INTERNAL int scm_i_print_char_set (SCM charset, SCM port,
                                        scm_print_state *pstate);
-SCM_INTERNAL void scm_init_srfi_14 (void);
+SCM_INTERNAL void scm_boot_srfi_14 (void);
 
 #endif /* SCM_SRFI_14_H */
diff --git a/libguile/unidata_to_charset.awk b/libguile/unidata_to_charset.awk
index 13692797a..848dfcb99 100644
--- a/libguile/unidata_to_charset.awk
+++ b/libguile/unidata_to_charset.awk
@@ -1,6 +1,6 @@
 # unidata_to_charset.awk --- Compute SRFI-14 charsets from UnicodeData.txt
 #
-# Copyright (C) 2009, 2010, 2022 Free Software Foundation, Inc.
+# Copyright (C) 2009, 2010, 2022, 2025 Free Software Foundation, Inc.
 #
 # This library is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Lesser General Public
@@ -79,7 +79,7 @@ BEGIN {
     all_charsets[all_charsets_count++] = "letter";
     all_charsets[all_charsets_count++] = "digit";
     all_charsets[all_charsets_count++] = "hex_digit";
-    all_charsets[all_charsets_count++] = "letter_plus_digit";
+    all_charsets[all_charsets_count++] = "letter_and_digit";
     all_charsets[all_charsets_count++] = "graphic";
     all_charsets[all_charsets_count++] = "whitespace";
     all_charsets[all_charsets_count++] = "printing";
@@ -203,7 +203,7 @@ category == "Lt" ||
 category == "Lm" ||
 category == "Lo" {
     charsets[charset_count++] = "letter";
-    charsets[charset_count++] = "letter_plus_digit";
+    charsets[charset_count++] = "letter_and_digit";
 }
 
 ## The digit character set
@@ -216,7 +216,7 @@ category == "Lo" {
 
 category == "Nd" {
     charsets[charset_count++] = "digit";
-    charsets[charset_count++] = "letter_plus_digit";
+    charsets[charset_count++] = "letter_and_digit";
 }
 
 ## The hex_digit character set
@@ -327,9 +327,9 @@ category !~ /Cs/ {
 ## Other character sets
 #######################
 
-# Note that the "letter_plus_digit" and "printing" character sets, which
+# Note that the "letter_and_digit" and "printing" character sets, which
 # are unions of other character sets, are included in the patterns
-# matching their constituent parts (i.e., the "letter_plus_digit"
+# matching their constituent parts (i.e., the "letter_and_digit"
 # character set is included as part of the "letter" and "digit"
 # patterns).
 #
diff --git a/module/ice-9/deprecated.scm b/module/ice-9/deprecated.scm
index bb0beab5d..c67cfa1e6 100644
--- a/module/ice-9/deprecated.scm
+++ b/module/ice-9/deprecated.scm
@@ -21,6 +21,7 @@
   #:use-module (ice-9 source-properties)
   #:use-module (ice-9 weak-tables)
   #:use-module (ice-9 arrays)
+  #:use-module (srfi srfi-14)
   #:export ((make-guardian* . make-guardian)
             module-observe-weak
             (make-object-property* . make-object-property)
@@ -44,17 +45,87 @@
             (array-index-map!* . array-index-map!)
             (array-equal?* . array-equal?)
             (array-slice-for-each* . array-slice-for-each)
-            (array-slice-for-each-in-order* . array-slice-for-each-in-order)))
+            (array-slice-for-each-in-order* . array-slice-for-each-in-order)
+            (char-set?* . char-set?)
+            (char-set=* . char-set=)
+            (char-set<=* . char-set<=)
+            (char-set-hash* . char-set-hash)
+            (char-set-cursor* . char-set-cursor)
+            (char-set-ref* . char-set-ref)
+            (char-set-cursor-next* . char-set-cursor-next)
+            (end-of-char-set?* . end-of-char-set?)
+            (char-set-fold* . char-set-fold)
+            (char-set-unfold* . char-set-unfold) char-set-unfold!
+            (char-set-for-each* . char-set-for-each)
+            (char-set-map* . char-set-map)
+            (char-set-copy* . char-set-copy)
+            (char-set* . char-set)
+            (list->char-set* . list->char-set)
+            (list->char-set!* . list->char-set!)
+            (string->char-set* . string->char-set)
+            (string->char-set!* . string->char-set!)
+            (char-set-filter* . char-set-filter)
+            (char-set-filter!* . char-set-filter!)
+            (ucs-range->char-set* . ucs-range->char-set)
+            (ucs-range->char-set!* . ucs-range->char-set!)
+            (->char-set* . ->char-set)
+            (char-set-size* . char-set-size)
+            (char-set-count* . char-set-count)
+            (char-set->list* . char-set->list)
+            (char-set->string* . char-set->string)
+            (char-set-contains?* . char-set-contains?)
+            (char-set-every* . char-set-every)
+            (char-set-any* . char-set-any)
+            (char-set-adjoin* . char-set-adjoin)
+            (char-set-adjoin!* . char-set-adjoin!)
+            (char-set-delete* . char-set-delete)
+            (char-set-delete!* . char-set-delete!)
+            (char-set-complement* . char-set-complement)
+            (char-set-union* . char-set-union)
+            (char-set-intersection* . char-set-intersection)
+            (char-set-difference* . char-set-difference)
+            (char-set-xor* . char-set-xor)
+            (char-set-diff+intersection* . char-set-diff+intersection)
+            (char-set-complement!* . char-set-complement!)
+            (char-set-union!* . char-set-union!)
+            (char-set-intersection!* . char-set-intersection!)
+            (char-set-difference!* . char-set-difference!)
+            (char-set-xor!* . char-set-xor!)
+            (char-set-diff+intersection!* . char-set-diff+intersection!)
+            (char-set:lower-case* . char-set:lower-case)
+            (char-set:upper-case* . char-set:upper-case)
+            (char-set:title-case* . char-set:title-case)
+            (char-set:letter* . char-set:letter)
+            (char-set:digit* . char-set:digit)
+            (char-set:letter+digit* . char-set:letter+digit)
+            (char-set:graphic* . char-set:graphic)
+            (char-set:printing* . char-set:printing)
+            (char-set:whitespace* . char-set:whitespace)
+            (char-set:iso-control* . char-set:iso-control)
+            (char-set:punctuation* . char-set:punctuation)
+            (char-set:symbol* . char-set:symbol)
+            (char-set:hex-digit* . char-set:hex-digit)
+            (char-set:blank* . char-set:blank)
+            (char-set:ascii* . char-set:ascii)
+            (char-set:empty* . char-set:empty)
+            (char-set:full* . char-set:full)))
 
-#;
-(define-syntax-rule (define-deprecated name message exp)
-  (begin
-    (define-syntax rule
-      (identifier-syntax
-       (begin
-         (issue-deprecation-warning message)
-         exp)))
-    (export rule)))
+(define-syntax define-deprecated/stx
+  (lambda (stx)
+    (syntax-case stx ()
+      ((_ mod id)
+       (let* ((id* (datum->syntax #'id
+                                  (symbol-append (syntax->datum #'id) '*)))
+              (msg (string-append
+                    (symbol->string (syntax->datum #'id))
+                    " in the default environment is deprecated.\n"
+                    "Import it from " (object->string (syntax->datum #'mod))
+                    " instead.")))
+         #`(define-syntax #,id*
+             (identifier-syntax
+              (begin
+                (issue-deprecation-warning #,msg)
+                #,#'id))))))))
 
 (define-syntax define-deprecated-trampoline
   (lambda (stx)
@@ -138,3 +209,102 @@
   (apply array-cell-ref array indices))
 (define-deprecated-trampoline (((ice-9 arrays) array-cell-set!) array val . indices)
   (apply array-cell-set! array val indices))
+
+(define-deprecated-trampolines (ice-9 arrays)
+  (array-fill! array fill)
+  (array-copy! src dst)
+  (array-copy-in-order! src dst)
+  (array-index-map! array proc))
+
+(define-deprecated-trampoline (((srfi srfi-14) char-set=) . char-sets)
+  (apply char-set= char-sets))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-hash) cs #:optional (bound 871))
+  (char-set-hash cs bound))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-unfold) p f g seed #:optional (base-cs (char-set)))
+  (char-set-unfold p f g seed base-cs))
+(define-deprecated-trampoline (((srfi srfi-14) char-set) . chars)
+  (list->char-set chars))
+(define-deprecated-trampoline (((srfi srfi-14) list->char-set) list #:optional (base-cs (char-set)))
+  (list->char-set list base-cs))
+(define-deprecated-trampoline (((srfi srfi-14) string->char-set) string #:optional (base-cs (char-set)))
+  (string->char-set string base-cs))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-filter) pred cs #:optional (base-cs (char-set)))
+  (char-set-filter pred cs base-cs))
+(define-deprecated-trampoline (((srfi srfi-14) ucs-range->char-set) lower upper
+                               #:optional error (base-cs (char-set)))
+  (ucs-range->char-set lower upper error base-cs))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-adjoin) cs . rest)
+  (apply char-set-adjoin cs rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-delete) cs . rest)
+  (apply char-set-delete cs rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-adjoin!) cs . rest)
+  (apply char-set-adjoin! cs rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-delete!) cs . rest)
+  (apply char-set-delete! cs rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-union) . rest)
+  (apply char-set-union rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-intersection) . rest)
+  (apply char-set-intersection rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-difference) cs . rest)
+  (apply char-set-difference cs rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-xor) . rest)
+  (apply char-set-xor rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-diff+intersection) cs . rest)
+  (apply char-set-diff+intersection cs rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-union!) . rest)
+  (apply char-set-union! rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-intersection!) . rest)
+  (apply char-set-intersection! rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-difference!) cs . rest)
+  (apply char-set-difference! cs rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-xor!) . rest)
+  (apply char-set-xor! rest))
+(define-deprecated-trampoline (((srfi srfi-14) char-set-diff+intersection!) cs . rest)
+  (apply char-set-diff+intersection! cs rest))
+(define-deprecated-trampolines (srfi srfi-14)
+  (char-set? x)
+  (char-set-cursor cs)
+  (char-set-ref cs cursor)
+  (char-set-cursor-next cs cursor)
+  (end-of-char-set? cursor)
+  (char-set-fold kons knil cs)
+  (char-set-unfold! p f g seed base-cs)
+  (char-set-for-each proc cs)
+  (char-set-map proc cs)
+  (char-set-copy cs)
+  (list->char-set! list base-cs)
+  (string->char-set! str base-cs)
+  (char-set-filter! pred cs base-cs)
+  (ucs-range->char-set! lower upper error base-cs)
+  (->char-set x)
+  (char-set-size cs)
+  (char-set-count pred cs)
+  (char-set->list cs)
+  (char-set->string cs)
+  (char-set-contains? cs ch)
+  (char-set-every pred cs)
+  (char-set-complement cs))
+
+(define-syntax-rule (define-deprecated*/stx mod id ...)
+  (begin
+    (define-deprecated/stx mod id)
+    ...))
+(define-deprecated*/stx (srfi srfi-14)
+  ;; Standard character sets
+  char-set:lower-case
+  char-set:upper-case
+  char-set:title-case
+  char-set:letter
+  char-set:digit
+  char-set:letter+digit
+  char-set:graphic
+  char-set:printing
+  char-set:whitespace
+  char-set:iso-control
+  char-set:punctuation
+  char-set:symbol
+  char-set:hex-digit
+  char-set:blank
+  char-set:ascii
+  char-set:empty
+  char-set:full)
diff --git a/module/ice-9/sandbox.scm b/module/ice-9/sandbox.scm
index c17e53282..7a2a7f1de 100644
--- a/module/ice-9/sandbox.scm
+++ b/module/ice-9/sandbox.scm
@@ -724,7 +724,7 @@ allocation limit is exceeded, an exception will be thrown to the
      string->number)))
 
 (define char-set-bindings
-  '(((guile)
+  '(((srfi srfi-14)
      ->char-set
      char-set
      char-set->list
diff --git a/module/language/elisp/lexer.scm b/module/language/elisp/lexer.scm
index f77f0c1c2..0394c4e03 100644
--- a/module/language/elisp/lexer.scm
+++ b/module/language/elisp/lexer.scm
@@ -21,6 +21,7 @@
 (define-module (language elisp lexer)
   #:use-module (ice-9 regex)
   #:use-module (ice-9 source-properties)
+  #:use-module (srfi srfi-14)
   #:export (get-lexer get-lexer/1))
 
 ;;; This is the lexical analyzer for the elisp reader.  It is
diff --git a/module/language/scheme/decompile-tree-il.scm b/module/language/scheme/decompile-tree-il.scm
index 99edee44c..6bb199e8c 100644
--- a/module/language/scheme/decompile-tree-il.scm
+++ b/module/language/scheme/decompile-tree-il.scm
@@ -1,6 +1,6 @@
 ;;; Guile VM code converters
 
-;; Copyright (C) 2001, 2009, 2012, 2013 Free Software Foundation, Inc.
+;; Copyright (C) 2001, 2009, 2012, 2013, 2025 Free Software Foundation, Inc.
 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -21,6 +21,7 @@
 (define-module (language scheme decompile-tree-il)
   #:use-module (language tree-il)
   #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-14)
   #:use-module (srfi srfi-26)
   #:use-module (ice-9 receive)
   #:use-module (ice-9 vlist)
diff --git a/module/rnrs/unicode.scm b/module/rnrs/unicode.scm
index 09140b6bf..ebcb1e571 100644
--- a/module/rnrs/unicode.scm
+++ b/module/rnrs/unicode.scm
@@ -1,6 +1,6 @@
 ;;; unicode.scm --- The R6RS Unicode library
 
-;;      Copyright (C) 2010 Free Software Foundation, Inc.
+;;      Copyright (C) 2010, 2025 Free Software Foundation, Inc.
 ;;
 ;; This library is free software; you can redistribute it and/or
 ;; modify it under the terms of the GNU Lesser General Public
@@ -69,9 +69,6 @@
 			char-upper-case?
 			char-lower-case?
 
-			char-set-contains?
-			char-set:title-case
-
 			char-general-category
 
 			char-upcase
@@ -92,6 +89,9 @@
 			string-normalize-nfkd
 			string-normalize-nfc
 			string-normalize-nfkc)
+          (only (srfi srfi-14)
+                char-set-contains?
+		char-set:title-case)
 	  (rnrs base (6)))
 
   (define (char-foldcase char)
diff --git a/module/srfi/srfi-14.scm b/module/srfi/srfi-14.scm
index ecc21e52e..97dcdf328 100644
--- a/module/srfi/srfi-14.scm
+++ b/module/srfi/srfi-14.scm
@@ -1,6 +1,6 @@
 ;;; srfi-14.scm --- Character-set Library
 
-;; 	Copyright (C) 2001, 2002, 2004, 2006 Free Software Foundation, Inc.
+;; 	Copyright (C) 2001, 2002, 2004, 2006, 2025 Free Software Foundation, Inc.
 ;;
 ;; This library is free software; you can redistribute it and/or
 ;; modify it under the terms of the GNU Lesser General Public
@@ -22,77 +22,81 @@
 
 ;;; Code:
 
-(define-module (srfi srfi-14))
+(define-module (srfi srfi-14)
+  ;; FIXME: Use #:export instead of #:replace once deprecated bindings
+  ;; are removed.
+  #:replace (;; General procedures
+             char-set?
+             char-set=
+             char-set<=
+             char-set-hash
 
-(re-export
-;;; General procedures
- char-set?
- char-set=
- char-set<=
- char-set-hash
+             ;; Iterating over character sets
+             char-set-cursor
+             char-set-ref
+             char-set-cursor-next
+             end-of-char-set?
+             char-set-fold
+             char-set-unfold char-set-unfold!
+             char-set-for-each
+             char-set-map
 
-;;; Iterating over character sets
- char-set-cursor
- char-set-ref
- char-set-cursor-next
- end-of-char-set?
- char-set-fold
- char-set-unfold char-set-unfold!
- char-set-for-each
- char-set-map
+             ;; Creating character sets
+             char-set-copy
+             char-set
+             list->char-set list->char-set!
+             string->char-set string->char-set!
+             char-set-filter char-set-filter!
+             ucs-range->char-set ucs-range->char-set!
+             ->char-set
 
-;;; Creating character sets
- char-set-copy
- char-set
- list->char-set list->char-set!
- string->char-set string->char-set!
- char-set-filter char-set-filter!
- ucs-range->char-set ucs-range->char-set!
- ->char-set
+             ;; Querying character sets
+             char-set-size
+             char-set-count
+             char-set->list
+             char-set->string
+             char-set-contains?
+             char-set-every
+             char-set-any
 
-;;; Querying character sets
- char-set-size
- char-set-count
- char-set->list
- char-set->string
- char-set-contains?
- char-set-every
- char-set-any
+             ;; Character set algebra
+             char-set-adjoin char-set-adjoin!
+             char-set-delete char-set-delete!
+             char-set-complement
+             char-set-union
+             char-set-intersection
+             char-set-difference
+             char-set-xor
+             char-set-diff+intersection
+             char-set-complement!
+             char-set-union!
+             char-set-intersection!
+             char-set-difference!
+             char-set-xor!
+             char-set-diff+intersection!
 
-;;; Character set algebra
- char-set-adjoin char-set-adjoin!
- char-set-delete char-set-delete!
- char-set-complement
- char-set-union
- char-set-intersection
- char-set-difference
- char-set-xor
- char-set-diff+intersection
- char-set-complement!
- char-set-union!
- char-set-intersection!
- char-set-difference!
- char-set-xor!
- char-set-diff+intersection!
+             ;; Standard character sets
+             char-set:lower-case
+             char-set:upper-case
+             char-set:title-case
+             char-set:letter
+             char-set:digit
+             char-set:letter+digit
+             char-set:graphic
+             char-set:printing
+             char-set:whitespace
+             char-set:iso-control
+             char-set:punctuation
+             char-set:symbol
+             char-set:hex-digit
+             char-set:blank
+             char-set:ascii
+             char-set:empty
+             char-set:full))
 
-;;; Standard character sets
- char-set:lower-case
- char-set:upper-case
- char-set:title-case
- char-set:letter
- char-set:digit
- char-set:letter+digit
- char-set:graphic
- char-set:printing
- char-set:whitespace
- char-set:iso-control
- char-set:punctuation
- char-set:symbol
- char-set:hex-digit
- char-set:blank
- char-set:ascii
- char-set:empty
- char-set:full)
+(eval-when (expand load eval)
+  (load-extension (string-append "libguile-" (effective-version))
+                  "scm_init_srfi_14"))
 
 (cond-expand-provide (current-module) '(srfi-14))
 
diff --git a/module/sxml/simple.scm b/module/sxml/simple.scm
index 57fccbc9c..9142852e5 100644
--- a/module/sxml/simple.scm
+++ b/module/sxml/simple.scm
@@ -1,6 +1,6 @@
 ;;;; (sxml simple) -- a simple interface to the SSAX parser
 ;;;;
-;;;; 	Copyright (C) 2009, 2010, 2013  Free Software Foundation, Inc.
+;;;; 	Copyright (C) 2009, 2010, 2013, 2025  Free Software Foundation, Inc.
 ;;;;    Modified 2004 by Andy Wingo <wingo at pobox dot com>.
 ;;;;    Originally written by Oleg Kiselyov <oleg at pobox dot com> as SXML-to-HTML.scm.
 ;;;; 
@@ -30,6 +30,7 @@
   #:use-module (sxml ssax)
   #:use-module (sxml transform)
   #:use-module (ice-9 match)
+  #:use-module (srfi srfi-14)
   #:export (xml->sxml sxml->xml sxml->string))
 
 ;; Helpers from upstream/SSAX.scm.
diff --git a/module/system/base/syntax.scm b/module/system/base/syntax.scm
index 9d4be1aa9..0b40287aa 100644
--- a/module/system/base/syntax.scm
+++ b/module/system/base/syntax.scm
@@ -1,6 +1,6 @@
 ;;; Guile VM specific syntaxes and utilities
 
-;; Copyright (C) 2001, 2009, 2016, 2019 Free Software Foundation, Inc
+;; Copyright (C) 2001, 2009, 2016, 2019, 2025 Free Software Foundation, Inc
 
 ;;; This library is free software; you can redistribute it and/or
 ;;; modify it under the terms of the GNU Lesser General Public
@@ -19,6 +19,7 @@
 ;;; Code:
 
 (define-module (system base syntax)
+  #:use-module (srfi srfi-14)
   #:export (%compute-initargs)
   #:export-syntax (define-type define-record define-record/keywords
                    record-case transform-record))
diff --git a/module/system/repl/server.scm b/module/system/repl/server.scm
index 9a8f51c5b..af6c67fd7 100644
--- a/module/system/repl/server.scm
+++ b/module/system/repl/server.scm
@@ -1,6 +1,6 @@
 ;;; Repl server
 
-;; Copyright (C) 2003,2010,2011,2014,2016,2019,2021 Free Software Foundation, Inc.
+;; Copyright (C) 2003,2010,2011,2014,2016,2019,2021,2025 Free Software Foundation, Inc.
 
 ;; This library is free software; you can redistribute it and/or
 ;; modify it under the terms of the GNU Lesser General Public
@@ -27,6 +27,7 @@
   #:use-module (ice-9 iconv)
   #:use-module (rnrs bytevectors)
   #:use-module (ice-9 binary-ports)
+  #:use-module (srfi srfi-14)
   #:use-module (srfi srfi-26)           ; cut
   #:export (make-tcp-server-socket
             make-unix-domain-server-socket
diff --git a/module/texinfo/serialize.scm b/module/texinfo/serialize.scm
index 05d3facae..da246a1e1 100644
--- a/module/texinfo/serialize.scm
+++ b/module/texinfo/serialize.scm
@@ -1,6 +1,6 @@
 ;;;; (texinfo serialize) -- rendering stexinfo as texinfo
 ;;;;
-;;;; 	Copyright (C) 2009, 2012, 2013  Free Software Foundation, Inc.
+;;;; 	Copyright (C) 2009, 2012, 2013, 2025  Free Software Foundation, Inc.
 ;;;;    Copyright (C) 2003,2004,2009  Andy Wingo <wingo at pobox dot com>
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
@@ -31,6 +31,7 @@
   #:use-module (ice-9 match)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-13)
+  #:use-module (srfi srfi-14)
   #:export (stexi->texi))
 
 (define (list-intersperse src-l elem)
diff --git a/module/texinfo/string-utils.scm b/module/texinfo/string-utils.scm
index 4b860fe74..937db7058 100644
--- a/module/texinfo/string-utils.scm
+++ b/module/texinfo/string-utils.scm
@@ -1,6 +1,6 @@
 ;;;; (texinfo string-utils) -- text filling and wrapping 
 ;;;;
-;;;;    Copyright (C) 2009, 2013  Free Software Foundation, Inc.
+;;;;    Copyright (C) 2009, 2013, 2025  Free Software Foundation, Inc.
 ;;;;    Copyright (C) 2003  Richard Todd
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
@@ -24,6 +24,7 @@
 ;;; Code:
 
 (define-module (texinfo string-utils)
+  #:use-module (srfi srfi-14)
   #:export (escape-special-chars
             transform-string
             expand-tabs
diff --git a/module/web/http.scm b/module/web/http.scm
index 9270cd0f9..567066bfc 100644
--- a/module/web/http.scm
+++ b/module/web/http.scm
@@ -36,8 +36,9 @@
   #:use-module (ice-9 object-properties)
   #:use-module (ice-9 rdelim)
   #:use-module (ice-9 textual-ports)
-  #:use-module (srfi srfi-19)
   #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-14)
+  #:use-module (srfi srfi-19)
   #:use-module (web uri)
   #:export (string->header
             header->string
diff --git a/module/web/uri.scm b/module/web/uri.scm
index 8c5c0d6f0..d57f4159e 100644
--- a/module/web/uri.scm
+++ b/module/web/uri.scm
@@ -1,6 +1,6 @@
 ;;;; (web uri) --- URI manipulation tools
 ;;;;
-;;;; Copyright (C) 1997,2001,2002,2010,2011,2012,2013,2014,2019-2021 Free Software Foundation, Inc.
+;;;; Copyright (C) 1997,2001,2002,2010,2011,2012,2013,2014,2019-2021,2025 Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -26,6 +26,7 @@
 
 (define-module (web uri)
   #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-14)
   #:use-module (ice-9 iconv)
   #:use-module (ice-9 regex)
   #:use-module (ice-9 rdelim)
diff --git a/test-suite/tests/strings.test b/test-suite/tests/strings.test
index c6df15844..0ffa51d6a 100644
--- a/test-suite/tests/strings.test
+++ b/test-suite/tests/strings.test
@@ -1,7 +1,7 @@
 ;;;; strings.test --- test suite for Guile's string functions    -*- scheme -*-
 ;;;; Jim Blandy <jimb@red-bean.com> --- August 1999
 ;;;;
-;;;; Copyright (C) 1999,2001,2004-2006,2008-2011,2013,2015,2018,2020,2023
+;;;; Copyright (C) 1999,2001,2004-2006,2008-2011,2013,2015,2018,2020,2023,2025
 ;;;;   Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
@@ -21,6 +21,7 @@
 (define-module (test-strings)
   #:use-module ((system base compile) #:select (compile))
   #:use-module (test-suite lib)
+  #:use-module (srfi srfi-14)
   #:use-module (ice-9 string-fun))
 
 (define exception:read-only-string
diff --git a/test-suite/tests/tree-il.test b/test-suite/tests/tree-il.test
index 2ec41864a..98343504e 100644
--- a/test-suite/tests/tree-il.test
+++ b/test-suite/tests/tree-il.test
@@ -27,7 +27,8 @@
   #:use-module (language tree-il optimize)
   #:use-module (ice-9 match)
   #:use-module (ice-9 regex)
-  #:use-module (srfi srfi-13))
+  #:use-module (srfi srfi-13)
+  #:use-module (srfi srfi-14))
 
 (define-syntax-rule (pass-if-primitives-resolved in expected)
   (pass-if (format #f "primitives-resolved in ~s" 'in)