December 13th, 2010 marked Satoshi’s last post on Bitcointalk and aside from some emails to Gavin Andresen in April 2011, his last “sign of life”:

Today Marks 10 Years Since Satoshi Nakamoto’s Last Public Activity

Satoshi Nakamoto is the pseudonymous creator of Bitcoin’s network. Plenty of people would like to know who this person (or group of people) might be, but to this date, this remains largely unknown.

What we do know is that on this date, back in 2010, Satoshi was last seen active on the popular Bitcointalk forum in a discussion on the network’s resistance to DoS attacks.

In any case, ever since then, the mysterious creator of the most popular cryptocurrency was never to be seen. To this date, there’s no publicly available and verifiable information that conclusively establishes the identity of Satoshi Nakamoto.

Full article here: https://cryptopotato.com/today-marks-10-years-since-satoshi-nakamotos-last-public-activity/