End of Production for A320ceo Family

The only issue is that, depending on scheduled delivery dates, Airbus may wish to complete the migration to the -neo before full execution of the order. As  earlier delivery dates may not be available (or as DL may not accept them), the manufacturer may be forced to postpone the end of -ceo production, or to build the last few frames in advance, unless of course the order is converted to the -neo.

I would not be surprised if the DL -ceo order was a sort of buffer designed to cushion Airbus against protracted -neo production problems, while DL would be happy to take -neo instead. There could be, for instance, a conversion clause in the sales purchase agreement, that could be activated by Airbus in case of termination of -ceo production. Of course, if that was the case, DL would enjoy favourable pricing, perhaps even -neo at -ceo price.

There is no evidence of the above, but I think there is a reason Airbus has been taking so many late -ceo orders.

Unfortunately, that is impossible, there must be a final -ceo production date, which -ceo vendors are entitled to be given early notice of. Airbus cannot keep them waiting without clear production prospects, when their contracts include minimum and maximum production levels. 

That still does not bring a migration. What has the time frame to do with clear production prospects? Airbus will simply inform the suppliers what parts are when needed. The ceo is to a big part build from the same parts as the neo, many changes were done in the years leading up to the neo, so that today it is in reality mainly the pylons and the engines themselves that make up the difference.