I don’t think it’s available as a settable option, but you could easily change the code that evaluates the user’s input against the $_SESSION variable to do a case-insensitive compare. These are off the top of my head and untested:
If it’s eForm that’s doing the check for example, you’d need to change this line (line 178 in eform.inc.php):
if($fields['vericode']!=$code) {
to
if (strtolower($fields['vericode']) != strtolower($code) ) {
or
if (strcasecmp($fields['vericode'], $code) == 0) {
Which might be a little faster.
WebLoginPE, OTOH, has
if ($_SESSION['veriword'] !== $formcode)
which could be changed to
if (strcasecmp($_SESSION['veriword'],formcode) != 0)
The Manager login comparison is in manager/processors/login.processor.php:
elseif ($_SESSION['veriword'] != $captcha_code) {
would change to
elseif (strcasecmp($_SESSION['veriword'],$captcha_code) != 0 ) {
Note that if the captcha words have non-English characters (e.g. é), you might need a more complicated comparison function.