ID4, as mentioned, was the shortened title of Independence Day. It was the 90s, and throwing numbers in titles that didn't need them still seemed cool (Se7en is really the only movie to get away with this). Well, the original proposed title for Independence Day 2 is ID Forever. Actually, ID Forever Part 1 and ID Forever Part 2. Shortened to ID4Ever? ID4eva? Hopefully not. Luckily, the ID Forever title has been out there so long that there's a pretty good chance it will in fact change.