How to obtain updated key

Hi
I bought 3DGamestudio Pro A6.1 i beleve a few years ago, I downloaded the trial version and then received the unlock key for that release. Now I've been in the process of upgrading my development environment twice and when I want to reinstall 3Dgamestudio I always need to install the first trial I downloaded with my purchase since the unlock key doesn't work with the latest build and then I need to install every update released until the latest build. Who can I write or contact to get the latest unlock key? so I just install the latest release instead of going to the whole process described above.
Thanks for replay

All keys are equal and it does not matter which trial version you install. You just need to install the latest update - 6.40 - AFTER installing and unlocking the trial version.