I updated CB to 2.1.3 Build 2018.01.01 on Joomla 3.8.3 using PHP 7.2 today, but CB update failed before cleanup with a HTTP 500 error (no more details even if detailed IIS HTTP error reporting is turned on).
After switching to CB in Joomla's admin panel, it showed me the correct version installed, but plugins archive file was still existing, so I should finalize the installation by clicking the link provided. With 7.2 an empty page appeared after following this link.
When I switched my site back to PHP 7.1, installation worked fine on my production site and I could finalize the installation on my test site.