Sirius 6.3.3 is a maintenance release with a single bugfix for Capella 1.4.2.
The complete list of (35) tickets fixed in Sirius 6.3.3 can be found here.
The release notes can be found .
It is recommended you use the update-site closest matching the version of Eclipse you use to avoid potential issues at runtime.
The complete JUnit and SWTBot test suites used to validate Sirius are published along with all their dependencies in separate update-sites from the core, available at: