For what it's worth, the current version of LINE for Android is 11.31.2.
When you go to the Play Store and search for "line app", and choose the selection titled "line app", you should then be offered the green INSTALL button.
If not, your Android system must truly be years out of date.
When, precisely, does that message appear? When you open Play Store? When you try to Install the LINE app? Provided with enough details, someone here with give you an explanation and advice on how to proceed.