The ship that sent the iceberg warning to Titanic has been located according to the BBC. The SS Mesaba was crossing the Atlantic Ocean on April 1912 and sent a wireless message to the Titanic about the ice it had spotted. The warning never reached the bridge. The SS Mesaba was sunk by a German torpedo in World War I and her remains in the Irish Sea were not located until recently. “ Now using state-of-the art multibeam sonar, Bangor University researchers have been able to identify the Mesaba’s wreck and pinpoint her final resting place.”

Source:

Titanic: Ship that sent iceberg warning found in Irish Sea
BBC, 27 Sept 2022