diff --git a/SC2181.md b/SC2181.md
index 361a660..b14d104 100644
--- a/SC2181.md
+++ b/SC2181.md
@@ -41,4 +41,4 @@ This also applies to `while`/`until` loops.
 
 ### Exceptions:
 
-None.
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+The default Solaris 10 bourne shells do not support '!' outside of a test statement (`if ! mycommand; then ...` returns `!: not found`)
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