No, games developed from, October onwards are required to include Neo mode.

Pretty sure its released... because otherwise what would be the develop date. Many games don't have an official start date of a game, it's usually pre-production... idea/mockups etc.

No way its developed from... what happens if I started pre-production in September, ... sorry GG makes no sense like that :)

Can you give us a source for that? A clear quote from Andrew House or Shawn Layden or even better the written parts of the guidelines sent to developers?

That would mean that every game announced until September 30th 2016 to be in development doesn't have to have a Neo mode, no matter when they release it. If Gearbox announces in September, that they started development of the Duke Nukem Forever successor, they don't have to care about a Neo mode?

That makes much more sense. Games that have been submitted to Sony until that date, but launch a few days later probably also get a pass. Perhaps even feature complete Betas, which aren't yet submitted to Sony for their okay.

But I highly doubt that any game still in development after October 1st can be released without a Neo mode, just because the development began earlier.

It seems you're right:

It makes sense to be release after 1st October other wise NEO would be kinda pointless as games been developed after October 2016 would be 2018/19 release dates rendering the NEO useless for 2-3 years with only a minority putting a NEO mode in if/until its install base became high enough to warrant it.

They don't need to buy a neo to play those games though. A standard PS4 would do fine.

I don't understand what isn't a good move by sony?

The Neo-Dev kits have been around for at least 3-4 months so far and initially all the developers need to do is guarantee 1080p as a minimum, then there is isn't much else for them to do to just meet requirements.

I wouldn't be surprised if Sony have asked specific developers to make pretty big changes to their games for October and it's a good indicator that launch of the machine is imminent.

Put youself in the developers position. You've been working on a game for two years and you're now in the polishing phase with a release date of October. Suddenly you find yourself having to not only polish the code but make it Neo compatible. That's going to annoy a few developers. If they'd mandated that games 'developed' after October require Neo mode then it would have been integrated into the development process from the beginning. It's till more work but not as bad as suddenly finding out you're not as close to completion as you thought, and it could in some circumstances lead to a delay.

But that would simply render the NEO useless for a few years as most games that would use extra specs of NEO would be AAA games and probably on a 2-3 year development cycle meaning games with NEO enabled mode wouldnt arrive until holiday 2018 and that is probably why they stated games after 1st October require a NEO mode.

Without that requirment date I would expect very few games maybe even close to zero games making use of it this holiday 2016 making a push for poeple to buy a NEO kinda pointless.

As you say, they have to polish and test the game anyway in that phase. If there are sequences in the game, where slowdowns occur and the 1080p/30fps target can't be met, they have to reduce the details or effects in that level/area of the game. If there are general performance problems which can't be fixed that easily, they have the option to reduce the resolution from 1080p to 900p for the PS4 version, which should give some performance headroom.

If they want it easy, they just keep the target of 1080p/30fps without these detail/effect/textures/resolution reductions for their Neo version. Sony doesn't force them to use 100% of the Neo performance.

If they are more ambitious, they may test and polish for a 1080p/60fps preset or a 1080p/30fps preset with better effects/antialiasing/shadows. But that extra effort is their own choice, not mandatory.

All 3D-engines are scalable nowadays, even on consoles. The final parameters aren't set in stone until the end of development... and even then they can be changed with patches.