Date for the ending of active hostilities between Britain and Germany - 11 11 1918 - well not quite 24 11 1918 - see the following
"In the Fall of 1918 Lettow invaded Rhodesia and on November 13th captured the town of Kasama - one of the only occasions on which a German Commander occupied British territory during the war. It was then, from a British POW, that Lettow learned of the armistice signed on November 11th ending the war and that the armistice terms included the evacuation of East Africa by Germany. Lettow had good stocks of cattle and ammunition; he had a regular influx of askaris to maintain an army; he was in no danger of being surrounded or defeated; he could have continued the war indefinitely. His first impulse was to fight his way from Rhodesia across the Congo and retire into Angola, where he would be impregnable.
He considered, however, that as a German soldier faithful to the fatherland he must honor the armistice. Lettow did so on November 23rd. Technically speaking, he did not surrender, but merely disbanded his troops and put himself at the disposal of the British commander"
sounds just like the story of the japanese soldier who had been sitting on an island for 25 years, not knowing that world war 2 was over... there must have been more outposts worldwide where the news of the armistice came through after november 11.
there are rumors that there are still some left stranded on the islands what was the last engagement in WWI by the way?
It depends how you define WWI. Given that Turkey did not ratify the original peace treaty you could say that its war with Britain over the Brussels Line and Mosul that ended in 1923 as legally still part of WWI (see the Mosul paper in smaller wrs you may have missed).
there are rumors that there are still some left stranded on the islands what was the last engagement in WWI by the way?
I think that the Australians and the Japanese cleared out the German Pacific possesions fairly effectively. However I have seen references to some Turkish garrisons in Arabia not surendering until December 1918. The problem seems to be two fold (1) communications in the Ottoman Empire were poor at the best of times so they may have not been told that an armistice had been signed and (2) some garrisons would not surrender until the British could guarantee them armed protection against the arabs. Given the ramshakle nature of the Ottoman Empire its possible that there were outposts in other parts that also didn't stand down when the armistice was signed.