no worries, Shearwater operates somewhat similar to Poseidon and Apeks instead of the rest of the scuba world. Poseidon has essentially had 3 designs of regulators *ignoring the Thor*. The Cyklon is all but identical to when it was released in 1958, and it still uses the same parts kit as it did back in 1958, they are all compatible. Same with the Jetstream, it has had a few different minor tweaks, but it is essentially the same as when it was released. The first stages have changed a bit, but there are still only a handful if them.
Apeks has had the same parts kits for all of it's second stages for the last what 20+ years? First stages have remained all but unchanged for the same time period, couple minor tweaks, but all basically the same as they were when they were released.
Changing is expensive and unnecessary when you have one of the best products on the market, you make small subtle improvements but as these companies are all premium brands they rely on repeat customers and word of mouth instead of huge advertising campaigns and releasing new products that are the latest and greatest thing rendering the old ones obsolete. Poseidon has had some iteration of the Cyklon 300 *the metal one* since 1958, and it is still selling now. It has gone through some major changes in the first stage department *Thank God!*, but the second stage is still the same because it just works.... Apeks is the same with their first and second stages, sure the XTX looks sexy and has the user changeable exhaust T's, and is now reversible, but the guts are still the same as the ATX series and the TX series before that which is at least 15 years old at this point. In contrast, how many different second stages do the rest of the market have with unique parts kits and all of that rendering the old ones obsolete or hard to find repair kits for, that's a great way to piss people off because their expensive piece of kit is now useless because of parts availability or lack thereof.
Shearwater doesn't want to create work for themselves, so they keep it simple, build the best damn computer in the world, and don't **** with it because you have a bad quarter or year and sales dipped and the marketing people say you need to bring the "wow factor" back to the consumers. Like I said, they redesigned the Predator for 3 reasons, 1st and foremost being they couldn't get the screen anymore, 2nd people wanted something smaller, 3rd they wanted to not have to use a weird irritating battery that not everyone would always have access to. The programming is still the same, the buttons are still the same, the overall look and feel is still the same, so the Predator isn't obsolete anymore, just had a facelift, same as the ATX going to the XTX from Apeks, no real functional improvements, just some nice tweaks to make it prettier and adapt to some market demand, but no need to reinvent the wheel.
This is why I support companies like Shearwater, Poseidon, Apeks etc, they aren't out to rip people off and they are still committed to the old school style of thinking. Unfortunately with Apeks being bought by Aqualung they are a bit harder to work with now *cough parts kits cough*, but the Brits are still sticking to their guns about the designs.
edit: sorry that was so long, it's a pet peeve of mine.... Also the little things like Apeks putting a yoke o-ring on the dust cap, or Shearwater making the battery O-ring a 112 DIN O-ring are the little things that tell you that divers are the ones making the decisions in these companies because it is all about the little things that make you go "huh, they really were thinking when they designed this". Sure they could have made that O-ring a different size to make it more optimal for the design of the unit, but the 112 O-ring is something every tech diver carries with them all the time so you never have to worry about some proprietary o-ring that you'll only ever use for your computer battery housing.
