There is an error when trying to install EhPortal 1.23 on SMF 2.1 RC1. Test faild with replacing code in Subs.php here:
<search position="replace"><![CDATA[ static $disabled;]]></search>
<add><![CDATA[ static $disabled, $default_disabled, $parse_tag_cache;]]></add>
That line of code has changed in RC1. It's now this:
static $disabled, $alltags_regex = '', $param_regexes = array();
Yes, beta testers had recently reported a few needed changes.
I will release an update within a day.
Eh Portal v1.24 has been released which includes adjustments for SMF 2.1-RC1.