[ksec]

Words from Apple News Circle were that Apple could not hire any talents in Machine Learning because Apple has rules and policy to disallow their employees publish anything ( even blog ) without approval. And that includes any research related technical documentation.

I guess in Machine Learning fields you will need these papers to prove your worth, not to mention the continuous improvement in ML across the whole industry. So after a few years Apple relented and allow them to publish these papers.

This slight changes of attitude has some effect on other department as well, including security research where now Apple at least participate in certain events.