Duplicate account check v3.0 changes: Added email address to notification email.
Duplicate account check v2.9 changes: Added check empty condition for superglobal variable.
Duplicate account check v2.8 changes: Fixed issue with null variable condition.
Duplicate account check v2.7 changes: Fixed issue where occasionally it would match with empty username.
Duplicate account check v2.6 changes: Now checks for deleted or rejected user accounts in order to avoid showing new registration as a duplicate account.
Duplicate account check v2.5 changes: Fixed issue where duplicate account matched with empty username
Duplicate account check v2.4 changes: Fixed issue with variable causing incorrect selection of duplicate accounts.
Duplicate account check v2.3 changes: Now only checks for duplicate account during new registrations.
Duplicate account check v2.2 changes: Fixed issue with Exclude usernames in options.
Duplicate account check v2.1 changes: Fixed issue with checking deleted accounts.
