diff --git a/shared-operations/src/wrappers/PdfFileJoi.ts b/shared-operations/src/wrappers/PdfFileJoi.ts
index adb02c713..6ecf94e5a 100644
--- a/shared-operations/src/wrappers/PdfFileJoi.ts
+++ b/shared-operations/src/wrappers/PdfFileJoi.ts
@@ -22,6 +22,6 @@ export const JoiPDFFileSchema = Joi.custom((value: Express.Multer.File[] /* <- a
     }
 }, "pdffile validation");
 
-function isPdfFileArray(value: any[]): value is PdfFile[] { // "is" is a ts-typeguard - https://www.typescriptlang.org/docs/handbook/advanced-types.html#user-defined-type-guards
+function isPdfFileArray(value: any[]): value is PdfFile[] { // "is" is a ts-typeguard - https://www.typescriptlang.org/docs/handbook/2/narrowing.html#using-type-predicates
     return value.every((e) => e instanceof PdfFile)
 } 
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