I am a software developer and I purchased a P2V+ about a year ago specifically to try my hand at drone SW development.
I read everywhere that there is an SDK for the P2V+ but on visiting developer.dji.com I can only find a link for "Mobile SDK". According to the documentation this SDK only seems to support P3 upwards. But to make sure, I compiled the sample app, copied it to an android Nexus 6P phone and tried to connect to the P2V+ remote control but it fails to connect.

Would someone be able to direct me to the correct link for the P2V+ SDK?

This seems to answer my question:

https://autoflightlogichelp.zend ... on-In-Autopilot-3-1

This appears to indicate that most of the non-DJI software written for the Phantom 2's is now unusable unless automatic updates are switched off on your phone or tablet (because most software vendors will support multiple DJI drones but cannot support more than one version of the SDK).  If you get caught out and an update takes place you have effectively locked out your Phantom 2 (for Apple devices) for the app you purchased.  I think you may also have problems with android devices as well because, although you can re-install the older version, it will no longer be on the app store.

Please somebody correct me if I am wrong in this assumption as I do not want to spread false information on here that will unfairly damage DJI's reputation.

The likelihood of my company buying any more DJI drones or choosing the DJI platform to develop any software on is now very unlikely as the shelf life of DJI drones going into the future appears to be far too short to merit even a small amount of software development. However I would appreciate it if somebody could give me a link to the last version of the SDK that did support the P2V+ so that my £1300+ purchase isn't a complete waste of money!   

The P2V+ could only support mobile SDK, but this particular forum is not necessarily the best source for SDK. It would be best to contact the Developer team directly at dev@dji.com or peruse the Developer Forum below:

http://forum.dev.dji.com/en

DJI-Jamie Posted at 2016-9-30 03:12
The P2V+ could only support mobile SDK, but this particular forum is not necessarily the best source ...

Thank you, I will try that forum.

alex@gaiatek.co Posted at 2016-9-30 12:02
Thank you, I will try that forum.

You're welcome, best of luck to you with your P2V+.