diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index f0203b39..f364c9a3 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1370,7 +1370,8 @@ Propeller Spin:
   type: programming
   lexer: Text only
   color: "#2b446d"
-  primary_extension: .spin
+  extensions:
+  - .spin
 
 Protocol Buffer:
   type: markup