Do not mix up the Studio version with the DB version. These are two different things. The only dependency is that for newer DB versions you need also the updated Studio/HANA tools versions.
The latest HANA Studio/HANA tools version is 2.3.5.
A list which Studio version corresponds to which DB version can be found in note 2073112. Newer Studio versions are backwards compatible to "older" DB versions.
Regards,
Florian