I’ve heard about the map for SP2, and the original SP1 islands are not mentioned. They may appear as Easter eggs, but if they don’t, here are some ideas on what could have happened.

-The big volcano island erupted and destroyed the original islands.
-The islands were destroyed in the testing of XML-edited explosives.
-The islands were a dream or nightmare, depending on how much you loved or hated the original map
-The islands eroded rapidly.
-The islands disappeared due to a ufo beam, similar to the ones used to steal cows in media.
-The islands are on the opposite point of the Simpleplanes planet.(Not Droo from J:NO, because none of them appear in that game)
-The islands are on another planet.
-The islands were mined out of existence for resources.
-The islands sank beneath the waves, maybe due to rising sea levels.
-The islands were on unstable ground and collapsed.
-The islands were a simulation.
-The islands were eaten by a gigantic monster.

I made most of these as jokes. Please do not take any of them seriously. They may all become invalid if the islands appear in SP2.