diff --git a/Rakefile b/Rakefile
index 673ba52..3b1eaef 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,10 +1,13 @@
 README = "readme.txt"
-SRC = ["prg-bib.php", "resize-iframe.js", README]
+PHP = "prg-bib.php"
+SRC = [PHP, "resize-iframe.js", README]
 GIT_TAG = `git describe --tag --exact-match`.chomp
 README_TAG = /^Stable tag: *(.*) *$/.match(open(README).read)[1]
+PHP_TAG = /\/*.*Version: *([^ ]*) *$/m.match(open(PHP).read)[1]
 ZIP = "prg-bib-#{README_TAG}.zip"
-raise "tag mismatch: #{GIT_TAG}(git), #{README_TAG}(#{README})" \
-      unless GIT_TAG == README_TAG
+raise("tag mismatch: #{GIT_TAG}(git), #{README_TAG}(#{README}), "+
+      "#{PHP_TAG}(#{PHP})") \
+      unless GIT_TAG == README_TAG && README_TAG == "v"+PHP_TAG
 changes=`git status --porcelain --untracked-files=no`.chomp
 raise "there are changes: #{changes}" unless changes.empty?
 
diff --git a/prg-bib.php b/prg-bib.php
index c307ec4..6c51bac 100644
--- a/prg-bib.php
+++ b/prg-bib.php
@@ -3,7 +3,7 @@
  * Plugin Name:       PRG Bibliography Shortcode
  * Plugin URI:        https://github.com/prg-titech/bib-shortcode/
  * Description:       Shortcode to embed publication lists.
- * Version:           0.1.1-alpha
+ * Version:           0.1.4-alpha
  * Requires at least: 5.2
  * Requires PHP:      7.2
  * Author:            Hidehiko Masuhara
diff --git a/readme.txt b/readme.txt
index 5d939a6..fe20520 100644
--- a/readme.txt
+++ b/readme.txt
@@ -3,7 +3,7 @@ Contributors: masuhara
 Tags: bibtex, bibliography, citation
 Requires at least: 5.2
 Tested up to: 6.6.1
-Stable tag: v0.1.3-alpha
+Stable tag: v0.1.4-alpha
 Requires PHP: 7.2
 License: GPL v2 or later
 License URI: https://www.gnu.org/licenses/gpl-2.0.html
@@ -22,7 +22,7 @@ Usage
 
 = How to update =
 1. Decide the release name (e.g., v0.1.3-alpha)
-2. Write the release name on Stable tag in readme.txt
+2. Write the release name on Stable tag in readme.txt and prg-bib.php.
 3. Add a Changelog section in readme.txt
 4. Locally commit changes
 5. Locally add a release tag (git tag v0.1.3-alpha)
@@ -34,6 +34,9 @@ Usage
 
 == Changelog ==
 
+- v0.1.4-alpha
+  FIX: check release tag in .php
+
 - v0.1.3-alpha
   FIX: .js and readme files are included.