diff --git a/.scripts/prepare.js b/.scripts/prepare.js
index 57f72fa2dc..0a267dc24e 100644
--- a/.scripts/prepare.js
+++ b/.scripts/prepare.js
@@ -207,15 +207,12 @@ async function generateChangeLog() {
 }
 
 
-const SEMVER_INCREMENTS = ['patch', 'minor', 'major', 'prepatch', 'preminor', 'premajor', 'prerelease'];
-const PRERELEASE_VERSIONS = ['prepatch', 'preminor', 'premajor', 'prerelease'];
+const SEMVER_INCREMENTS = ['patch', 'minor', 'major'];
 
 const isValidVersion = input => Boolean(semver.valid(input));
 
 const isValidVersionInput = input => SEMVER_INCREMENTS.indexOf(input) !== -1 || common.isValidVersion(input);
 
-const isPrereleaseVersion = version => PRERELEASE_VERSIONS.indexOf(version) !== -1 || Boolean(semver.prerelease(version));
-
 function getNewVersion(oldVersion, input) {
   if (!isValidVersionInput(input)) {
     throw new Error(`Version should be either ${SEMVER_INCREMENTS.join(', ')} or a valid semver version.`);