diff --git a/source/services/member.ts b/source/services/member.ts
index 8363318..15b5354 100644
--- a/source/services/member.ts
+++ b/source/services/member.ts
@@ -87,7 +87,7 @@ namespace _espe.service.member
 						(x : string) => x.replace(new RegExp("[öÖ]", "g"), "oe"),
 						(x : string) => x.replace(new RegExp("[üÜ]", "g"), "ue"),
 						(x : string) => x.replace(new RegExp("[ß]", "g"), "ss"),
-						(x : string) => x.replace(new RegExp("[^a-z-\.]", "g"), "_"),
+						(x : string) => x.replace(new RegExp("[^0-9a-z-\.]", "g"), "_"),
 					]
 				),
 				"extension": (