diff --git a/ReleaseNotesBundle/Command/GitChangelog.sh b/ReleaseNotesBundle/Command/GitChangelog.sh
index ca1e0b0..b5c29a0 100644
--- a/ReleaseNotesBundle/Command/GitChangelog.sh
+++ b/ReleaseNotesBundle/Command/GitChangelog.sh
@@ -1,12 +1,10 @@
 #!/bin/bash
 
 #get tag of actual version
-actualVersionTag=$(git tag | tail -1)
-actualVersionHash=$(git rev-list -n 1 $actualVersionTag)
+ACTUAL_VERSION_TAG=$(git tag | tail -1)
 
 #get tag of the version before actual version
-beforeVersionTag=$(git tag | tail -3 | head -n 1)
-beforeVersionHash=$(git rev-list -n 1 $beforeVersionTag)
+PREVIOUS_VERSION_TAG=$(git tag | tail -3 | head -n 1)
 
 #echo $listOfTickets
-git log --pretty="format:%s" $beforeVersionHash..$actualVersionHash
\ No newline at end of file
+git log --pretty="format:%s" "$PREVIOUS_VERSION_TAG".."$ACTUAL_VERSION_TAG"
diff --git a/composer.json b/composer.json
index 5cc75f2..b0240cb 100644
--- a/composer.json
+++ b/composer.json
@@ -4,10 +4,10 @@
   "keywords": ["log","logging","git log"],
   "require": {
     "php": ">=7.0.0",
+    "ext-json": "*",
     "phpunit/phpunit": "^8.5",
     "symfony/console": "*",
     "guzzlehttp/guzzle": "*"
-
   },
   "license": "MIT",
   "authors": [