You can always leave it in semi.

 

Not sure if you're serious? WHY would they do that? So now you can't just throw in any carrier of your choosing (w/o modding it first). They didn't originally plan that mod. But now they do that because they felt (or were told) that a mil spec carrier with their trip would NOT "pass go". So now they add a carrier, proprietary to their trigger group, OBVIOUSLY with the hopes of a "pass go" from the ATF.
But no... they keep on keepin' on with their BS line of "oh, we has coating issues, blah blah blah". Fast forward almost a year (dang, that's one hell of a coating issue! LOL) and we STILL do not see these in the wild (gee, wonder why).
If Fostech would man up and decide to be honest, for once, maybe I'd have a smidgeon more respect for them. But at the rate they are going (and the constant BS from them) NO.
I'm calling them out: I believe they do NOT have approval for this trigger. Period. And all the delays are due to that (despite the carrier mods).
But again, the carrier. There is NO need to modify a carrier for this design. They could have reshaped the TRIP instead (but obviously didn't for a reason... the one above). The original design utilized a mil spec carrier. They now use a modified one for a reason (back to their dishonesty about the delays).
Vaporware, proprietary carrier, difficult to get refund, dishonesty (about delays and status), going "dark" and leaving their customers wondering, etc.
 I finally received my refund (after 3 email attempts and finally a semi threatening letter to file CC fraud) and I'll not touch ANYTHING they make ever again.
To each their own.

I suspect they modified the carrier for reliability purpose. Remember, Franklin Armory had to modify their design too; that's why they are on Generation 2 of their trigger.

And, BTW, you don't need ATF "approval" for your trigger. It's legal to have a trigger that fires on release, and always has been (look at top competitors in skeet).

What you do have to make sure of is that it's not "easily" converted to full-auto by the end user. Franklin Armory had to do the same thing.

My AR 9mm pistol has a proprietary bolt; so does my TNW rifle. Both function flawlessly.

Fostech got ahead of their skis when they announced availability in first quarter 2016, just  like Kel-tec did with the PMR pistol (and pretty much anything they've ever made).
Fostech is a small company, not much bigger than a LGS. My guess is that they are learning from this experience. I don't mind giving them a chance.

G.

There is a difference between "fires on release" (as in skeet) and "binary". YES, you do need ATF approval for binary. Those "fire on release" skeet triggers are still a ONE function trigger (pull does not fire, release fires). A binary trigger does DUAL function (fire on pull, fire on release). I tire of people comparing competition "fire on release" triggers to binary triggers. Completely different animal. I'm actually surprised ANY binary trigger gets approved. The legal definition is "one fire per action of the trigger". ATF has concluded that both the pull and release are TWO distinct actions (all good there)... HOWEVER... they also state that neither action can be "assisted" by any means other than mechanical manipulation by the user. Triggers have a reseat/return spring, which means ONE of those actions is "assisted". Wouldn't matter for a "fire on pull" or a "fire on release", since they are still ONE fire per action. However, a binary trigger fires on PULL (one action, all good) AND release (not good, since that's "return spring assisted", thus making ONE of those actions non user manipulated). "Release" is not an action, as if you slide your finger off the trigger... did you return/fire it? No. It did so itself, under return spring tension (not an issue for ONE shot, but since also fired on PULL, that makes the second shot NON manipulated by user... thus "multi fire" or MG). I'm not a lawyer, but I can tell you they probably WILL wake up to this "contradiction" eventually.
I do agree, however, the Fostech got WAY ahead of itself and should have waited for approval PRIOR to disclosing (and accepting pre order) of it's release (which has yet to happen).

Emphasized the important bit for you.
I think it's clear to everyone but you that you are wrong there.

Yep.
Hell, the ATF "approval", came in what, the late 80's, in regards to the MIni 14 triggers getting modified to fire on pull, and on release.

There is no regulation or ruling that a dual function trigger requires approval by the ATF.

People who are spending the thousands of dollars to bring these to market submit their design to ATF so that they won't be faced with a recall resulting in bankruptcy (the ATF can require a company to recall their product....think Can Cannon).

There have been small manufacturers selling similar designs for a few years now (very quietly I might add) that haven't received approval from any government agency, recalling the trigger designs from the 1980's that did the same thing.
The ATF had previously stated that dual function triggers were legal. Period.

You only submit a design to them if you think it might be in conflict with administrative law in the future and you're trying to prevent that from happening (a very good business model). It's not required by law.

G.