How many AppInventor?

I have a problem, do not know the difference between these two AppInventor ...

1) http://services.appinventor.mit.edu

2) http://ai2.appinventor.mit.edu

Thanks in advance to those who will give me an answer

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1) this is an outdated test version of the services feature, which still needs loads of work, I recommend you to NOT use that server

2) this is the main App Inventor server you should use

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The n) 1 server allows you to work background apps, why not recommend to use it?

thanks a lot for your valuable help

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The services implementation is not ready for general use because interaction with Android power management.
We're studying the issue but don't have a clear solution yet.

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thanks a lot to everyone

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