Yesterday we released an update to the SilverStripe CMS. As it fixes security vulnerabilities in our software, we recommend that production websites should upgrade to this version.
No API changes are generated in this release, so existing modules and websites should upgrade easily. Related to this release, we also issued a security update for the SilverStripe forum module.
On the topic of security, we recently updated developer documentation on security that we suggest SilverStripe developers read.