A new 5.3 patch update is available from the Support portal. This patch includes improvements in the SOLR search integration to support full text indexing of published Pages & Assets, in addition to Page / Asset metadata, and several security updates to system components, including the DTS Tomcat server.
More information can be found in the Patch release notes.
The patch can be downloaded from the Support Portal.
Let us know if you have any questions about the patch.