Error: Call to undefined function Craft\mb_convertOcase() after updating to 2.6.3017 Just updated Craft 2.6.3002 to 2.6.3017 and am getting the following error in the CP &amp; front-end: Call to undefined function Craft\mb_convertOcase() /craft/app/helpers/StringHelper.php(558). On line 558 of this file, I have return mb_convert_case($string, MB_CASE_UPPER, static::UTF8);. Where is O coming from?

Screenshot of error &amp; stack trace:
I performed a manual upgrade as documented at https://docs.craftcms.com/v2/updating.html#manually-updating and the error automagically disappeared. Therefore, it looks like there was a glitch in the One-click Updating in this particular case.