Interesting. I thought the revolution was a wholly Russian affair and thus the 1919 end date is given because those who died in mine-clearance and ordnance disposal mishaps and the like were counted as war casualties, thus effectively extending the period deemed to be war service into that fifth year.
The scuttling of the German High Sea Fleet in Scapa Flow was 21st June 1919.
Information was being deliberately with held from the Germans. They knew that the peace treaty was due to be signed and suspected that part of the deal would involve the surrender and handing over the vessels.
As such Admiral Von Reuter decided on his own accord that scuttling would be preferable to surrender.
Obviously we responded very well and machine gunned unarmed German sailors in their life boats.
9 killed and 16 wounded.