Naturally, Dr. Kalam could not speak about these issues when he was the President due to the "Code of Conduct" and the "Code of Secrecy" that you mention.
But now that he is no longer the President, his lips are no longer sealed.
And, for Heaven's sake, he is not revealing any classified or confidential information.
And regarding "Media Bytes", does a Living Legend like Dr. Kalam need to resort to giving "Media Bytes?"