diff --git a/tools/utils/docker.ts b/tools/utils/docker.ts
index 913de449792afd388b64cf1c6425a74e5c1f7423..c7869752f340a6b851724010424f68fe55a671e2 100644
--- a/tools/utils/docker.ts
+++ b/tools/utils/docker.ts
@@ -32,7 +32,7 @@ export async function bake(
   if (opts.version) {
     console.log(`Using version: ${opts.version.version}`);
     process.env.RENOVATE_VERSION = opts.version.version;
-    if (!opts.version.prerelease) {
+    if (!opts.version.prerelease.length) {
       process.env.RENOVATE_MAJOR_VERSION = `${opts.version.major}`;
       process.env.RENOVATE_MAJOR_MINOR_VERSION = `${opts.version.major}.${opts.version.minor}`;
     }