diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6f489ab..f8eeea8 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -20,7 +20,6 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         emacs-version:
-          - 27.2
           - 28.2
           - 29.4
         experimental: [false]
@@ -34,9 +33,6 @@ jobs:
           - os: windows-latest
             emacs-version: snapshot
             experimental: true
-        exclude:
-          - os: macos-latest
-            emacs-version: 27.2
 
     steps:
     - uses: actions/checkout@v4
diff --git a/Eask b/Eask
index dad6b47..8d430ae 100644
--- a/Eask
+++ b/Eask
@@ -13,7 +13,7 @@
 (source "melpa")
 (source "jcs-elpa")
 
-(depends-on "emacs" "27.1")
+(depends-on "emacs" "28.1")
 (depends-on "sideline")
 
 (setq network-security-level 'low)  ; see https://github.com/jcs090218/setup-emacs-windows/issues/156#issuecomment-932956432
diff --git a/sideline-flymake.el b/sideline-flymake.el
index a0f903a..6a209a9 100644
--- a/sideline-flymake.el
+++ b/sideline-flymake.el
@@ -6,7 +6,7 @@
 ;; Maintainer: Shen, Jen-Chieh <jcs090218@gmail.com>
 ;; URL: https://github.com/emacs-sideline/sideline-flymake
 ;; Version: 0.1.0
-;; Package-Requires: ((emacs "27.1") (sideline "0.1.0"))
+;; Package-Requires: ((emacs "28.1") (sideline "0.1.0"))
 ;; Keywords: convenience flymake
 
 ;; This file is not part of GNU Emacs.