Do you think we can always use nightly build for each 'customer specific' updates on production server or it's recommanded to keep the same version until next release (like 7.1) ?

@Clément THOMAS: as they say "if it ain't broke don't fix it". Surely you are not going to update the client's code every day? If there is a need to update to fix something that is broken, download a nightly, run tests on it, and when you are satisfied, effect the update. As a general rule, test at home before dumping it onto a client.

Thanks for your response : it's easy to say but it's boring to do, in accordance with number of functional things to test, generally, if we do an update, we test only functional flows related to the update. Other errors exceptionally returned by customer are processed as bug-fix. Maybe I should try to use unit test but it's another subject.

Nightly is not so stable. Eg: try to install the portal module on openerp-7.0-20131202-002354.tar.gz .It is not a bug, it will simply crash. I would like to know if there is anything more stable than that. Maybe a nightly build that has been tested and has some sort of warrant that at least it will work.

same as I see I developed a test module . when I use an older version the module work fine :) when I use it in the last version the fields are stored in tables but did not shows in the views !!! http://www.mediafire.com/download/428zhr6vcrf5uwm/test.tar.bz2

It is a community driven project. I saw some issues and I was not sure it is a really a bug. If you go back to fundamental of software development life cycle, official release is fully tested and qualified release. If you go to OpenERP website and request for download it downloads nightly build and it is mentioned as stable. Complex products like OpenERP requires more than a week to test and qualify.So any developers who download will have concern. I have expressed concern based on my experience with it.