Is expiation obligatory for one who swore a false oath upon the Qur’an nine years ago with the intention of giving false testimony, and then the aggrieved party dropped the case?

Bearing false witness is among the gravest of major sins, especially when accompanied by a Yamin (definition) Ghamus (a perjured oath taken knowingly and falsely), as mentioned in the Prophetic Tradition. The immediate duty is to repent to Allah from this great sin by seeking forgiveness, expressing remorse, and resolving never to return to it. Scholars have differed regarding the expiation for a Yamin Ghamus: some say there is no expiation for it due to its severity, while others say it can be expiated. As for the ruling issued against those testified against, you are not bound by anything if the rightful claimant relinquishes their right. If you can seek their forgiveness, then do so; otherwise, seeking forgiveness, expressing remorse, and resolving never to return to it will suffice.