diff --git a/dip-0005.md b/dip-0005.md
index 5499465..ba88be9 100644
--- a/dip-0005.md
+++ b/dip-0005.md
@@ -166,7 +166,7 @@ The username field of the Register SubTx must meet the following criteria:
 
 - Minimum length: 3 characters
 - Maximum length: 24 characters
-- Acceptable characters: `A-Z` (case insensitive); `0-9`; underscore `_`; period `.`
+- Acceptable characters: `A-Z` (case insensitive); `0-9`;
   - Note: Usernames are validated as all lowercase characters regardless of the case in the SubTxRegister
 - Unique across the Dash blockchain and current mempool
 - Immutable - the username of a Blockchain User cannot be changed