Sybase/ASE DB Server 15.7 support for JDBC 4.2

According to below post SDK15.7 Sp138 and higher supports JDBC 4.2:

https://answers.sap.com/questions/155909/jconnect-jdbc-41-or-42-driver.html

However, using jconn4 SP139, when I run against my Sybase 15.7 DB server DatabaseMetaData.getJDBCMajorVersion() & DatabaseMetaData.getJDBCMajorVersion(), I get 4.0 (*not* 4.2) for the JDBC version.

Do I have to do some upgrade on the server side in order to get JDBC 4.2 support ?
Note: running sp_version stored proc, I get following info:
installmaster 15.7.0/EBF 20373 SMP ESD#2/P/x86_64/Enterprise Linux/ase157esd2/3109/64-bit.
Thank you very much in advance for your time and your expertise.
Best Regards
n.t.