diff --git a/services/user.py b/services/user.py
index 21759b07..95e58aaa 100644
--- a/services/user.py
+++ b/services/user.py
@@ -10,10 +10,9 @@
 
 
 def check_stil_id(s: str) -> bool:
-    if not len(s) == 10:
-        return False
-    pattern = r"^[a-z]{2}\d{4}[a-z]{2}-s$"
-    return bool(re.fullmatch(pattern, s))
+    pattern1 = r"^[a-z]{2}\d{4}[a-z]{2}-s$"   # current format: ab1234cd-s
+    pattern2 = r"^[a-z]{3}\d{2}[a-z]{3}$"     # old format:     abc12def
+    return bool(re.fullmatch(pattern1, s) or re.fullmatch(pattern2, s))
 
 
 def condition(model, asset):