TLS support is dependent on JDK runtime you are using to run the server.
First JDK runtime to support TLS 1.2 was JDK7.
So you would first need to upgrade to such runtime, but AS 4.2.3 might have issue with this version of JDK.
Best thing you could do is upgrade to bit more recent AS version.
Currently latest is 11.
Thank you so much for your answer!