I looked through the forum and it appears the blue diamond cardboard packages for engines were introduced in 1971. When were they replaced with the cardboard backed plastic bubble packaging? The 1981 catalog is the first to specify that Solar Igniters were shipped with all Estes motors. I don't think any engines were shipped with the solar igniters in the blue diamond boxes, so I'm pretty sure it was before 1981 that those boxes were retired. I also don't remember receiving any D-engines in the blue diamond packaging. I think I got my first D-engine rocket in 1978, the Estes Mean Machine in the first year of its release, and only remember the newer packaging for D engines. Perpaps the blue dimond packaging was replaced by 1978 for all engines.