diff --git a/lib/workers/common.ts b/lib/workers/common.ts
index 9e4cfe28e91b5cea8fec14da41f9e22897213f09..da26efba8117996f65a71bf57ac95d4cf0d7c527 100644
--- a/lib/workers/common.ts
+++ b/lib/workers/common.ts
@@ -35,6 +35,7 @@ export interface BranchUpgradeConfig
   packageFile?: string;
 
   parentBranch?: string;
+  prBanner?: string;
   prBodyNotes?: string[];
   prBodyTemplate?: string;
   prPriority?: number;
diff --git a/lib/workers/pr/body/banner.ts b/lib/workers/pr/body/banner.ts
index 431c9606ed8d982e740d53d67ccef3b541349992..4a18283eee790e846996da6dffc4090659b14b67 100644
--- a/lib/workers/pr/body/banner.ts
+++ b/lib/workers/pr/body/banner.ts
@@ -12,5 +12,5 @@ export function getPrBanner(config: BranchConfig): string {
   if (!config.prBanner) {
     return '';
   }
-  return template.compile(config.prBanner.toString(), config) + '\n\n';
+  return template.compile(config.prBanner, config) + '\n\n';
 }