diff --git a/tools/make-firefox-meta.py b/tools/make-firefox-meta.py
index 26e595207..72e0c280e 100644
--- a/tools/make-firefox-meta.py
+++ b/tools/make-firefox-meta.py
@@ -76,7 +76,7 @@ with open(chromium_manifest, encoding='utf-8') as m:
 # https://developer.mozilla.org/en-US/Add-ons/AMO/Policy/Maintenance#How_do_I_submit_a_Beta_add-on.3F
 # "To create a beta channel [...] '(a|alpha|b|beta|pre|rc)\d*$' "
 if sys.argv[2]:
-    manifest['version'] += '-' + sys.argv[2]
+    manifest['version'] += sys.argv[2]
 
 manifest['homepage'] = 'https://github.com/gorhill/uBlock'
 manifest['description'] = descriptions['en']