diff --git a/job_creator.php b/job_creator.php
index 433fae9..2620e15 100644
--- a/job_creator.php
+++ b/job_creator.php
@@ -477,8 +477,8 @@ public function createJson(string $yml): string
         $inputs = $this->getInputs($yml);
         // $myRef will either be a branch for push (i.e cron) and pull-request (target branch), or a semver tag
         $myRef = $inputs['github_my_ref'];
-        $isTag = preg_match('#^([0-9]+)\.([0-9]+)\.[0-9]+$#', $myRef, $m)
-            || preg_match('#^([0-9]+)\.([0-9]+)\.[0-9]+-(alpha|beta|rc)[0-9]+$#', $myRef, $m);
+        $unstableTagRx = '#^([0-9]+)\.([0-9]+)\.[0-9]+-((alpha|beta|rc))[0-9]+$#';
+        $isTag = preg_match('#^([0-9]+)\.([0-9]+)\.[0-9]+$#', $myRef, $m) || preg_match($unstableTagRx, $myRef, $m);
         $this->branch = $isTag ? sprintf('%d.%d', $m[1], $m[2]) : $myRef;
 
         // parent branch is a best attempt to get the parent branch of the branch via bash
@@ -489,6 +489,9 @@ public function createJson(string $yml): string
 
         $this->githubRepository = $inputs['github_repository'];
         $this->installerVersion = $this->getInstallerVersion();
+        if (preg_match($unstableTagRx, $myRef, $m)) {
+            $this->installerVersion = str_replace('.x-dev', '.0-' . $m[3] . '1', $this->installerVersion);
+        }
 
         $run = [];
         $extraJobs = [];
diff --git a/tests/JobCreatorTest.php b/tests/JobCreatorTest.php
index 00ae69c..e4c4247 100644
--- a/tests/JobCreatorTest.php
+++ b/tests/JobCreatorTest.php
@@ -576,7 +576,7 @@ public function provideGitHubMyRefTags(): array
         return [
             ['4.10', '4.10.x-dev'],
             ['4.10.6', '4.10.x-dev'],
-            ['5.0.0-beta1', '5.0.x-dev'],
+            ['5.0.0-beta2', '5.0.0-beta1'],
         ];
     }