[elpa] externals/bnf-mode a2a9a7471e: Drop support for Emacs versions older than 27.1

[ELPA Syncer]

branch: externals/bnf-mode
commit a2a9a7471ed2bd1f1e132a41e70f9a04934898c3
Author: Serghei Iakovlev <egrep@protonmail.ch>
Commit: Serghei Iakovlev <git@serghei.pl>

    Drop support for Emacs versions older than 27.1
---
 .github/workflows/build.yml | 15 ---------------
 NEWS                        | 12 +++++++-----
 README.org                  |  9 +++++----
 bnf-mode.el                 |  2 +-
 bnf-mode.texi               | 10 +++++-----
 5 files changed, 18 insertions(+), 30 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b0b00ba934..3b9d98d614 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -37,25 +37,10 @@ jobs:
 
       matrix:
         emacs_version:
-          # 2016-09 - 2017-09
-          - '25.1'
-          - '25.2'
-          - '25.3'
-
-          # 2018-05 - 2019-08
-          - '26.1'
-          - '26.2'
-          - '26.3'
-
-          # 2020-08 - 2021-03
           - '27.1'
           - '27.2'
-
-          # 2022-04 - 2022-09
           - '28.1'
           - '28.2'
-
-          # 2023-07 - 2024-06
           - '29.1'
           - '29.2'
           - '29.3'
diff --git a/NEWS b/NEWS
index 46e19e3847..e891730d2f 100644
--- a/NEWS
+++ b/NEWS
@@ -6,11 +6,13 @@ See the end of the file for license conditions.
 This file is about changes in BNF Mode.
 
 * BNF Mode 0.5.0
-** GNU Emacs < 25.1 is no longer supported.
-Due to difficulties in setting up the environment and test automation, the
-version of GNU Emacs older than 25.1 is no longer officially supported. BNF 
Mode
-may still work with older versions of GNU Emacs, like 24.3, or with other
-flavors of Emacs (e.g. XEmacs) but this is not guaranteed anymore.
+** GNU Emacs < 27.1 is no longer supported.  Support for versions of
+GNU Emacs older than 27.1 has been discontinued, primarily due to the
+adoption of more modern APIs, such as `rx-define', and the increased
+complexity of CI workflows required for maintaining older versions.
+If you are still using GNU Emacs versions older than 27.1 or other
+Emacs flavors (e.g., XEmacs), please continue using an earlier version
+of BNF Mode.
 
 * BNF Mode 0.4.5
 ** Tests were migrated from ert-runner to buttercup.
diff --git a/README.org b/README.org
index 479a14a7fb..403a7a987e 100644
--- a/README.org
+++ b/README.org
@@ -33,10 +33,11 @@ When developing this mode, the following documents were 
taken into account:
 
 ** Installation
 
-Known to work with GNU Emacs 25.1 and later.  BNF Mode may work with
-older versions of Emacs, or with other flavors of Emacs (e.g. XEmacs)
-but this is /not/ guaranteed.  Bug reports for problems related to using
-BNF Mode with older versions of Emacs will most like not be addressed.
+The current version of BNF Mode known to work with GNU Emacs 27.1 and
+later.  It may still function with older versions of Emacs, or with
+other flavors of Emacs (e.g. XEmacs) but this is /not/ guaranteed.  Bug
+reports for problems related to using this version of BNF Mode with
+older versions of Emacs will most like not be addressed.
 
 The master of all the material is the Git repository at
 https://github.com/sergeyklay/bnf-mode .
diff --git a/bnf-mode.el b/bnf-mode.el
index 4605e2d938..bade8c6c32 100644
--- a/bnf-mode.el
+++ b/bnf-mode.el
@@ -7,7 +7,7 @@
 ;; Version: 0.4.5
 ;; URL: https://github.com/sergeyklay/bnf-mode
 ;; Keywords: languages
-;; Package-Requires: ((cl-lib "0.5") (emacs "25.1"))
+;; Package-Requires: ((cl-lib "0.5") (emacs "27.1"))
 ;; Revision: $Format:%h (%cD %d)$
 
 ;;;; License
diff --git a/bnf-mode.texi b/bnf-mode.texi
index 6f4587e34d..abfe8f60d2 100644
--- a/bnf-mode.texi
+++ b/bnf-mode.texi
@@ -127,11 +127,11 @@ Bellow canonical BNF notation represented with a BNF is 
presented.  The syntax o
 
 @cindex Installation
 
-BNF Mode known to work with GNU Emacs 25.1 and later.  BNF Mode may
-work with older versions of Emacs, or with other flavors of Emacs
-(e.g. XEmacs) but this is @i{not} guaranteed.  Bug reports for problems
-related to using BNF Mode with older versions of Emacs will most like
-not be addressed.
+The current version of BNF Mode known to work with GNU Emacs 27.1 and
+later.  It may still function with older versions of Emacs, or with
+other flavors of Emacs (e.g. XEmacs) but this is @i{not} guaranteed.
+Bug reports for problems related to using this version of BNF Mode
+with older versions of Emacs will most like not be addressed.
 
 @menu
 * Installing from Elpa or Melpa::