I already mentioned the possibility of Leica not releasing a new digital M rangefinder for Photokina this year. This has been pretty much the consensus of all tips and emails I received in the past few weeks. With the exception of one tip, we have not seen any leaks or indications that a new M is coming soon (usually we always see some leaks prior to an announcement).
There are still two weeks left until the big show in Germany and I still have a hard time believing all of this, since 2016 is also the 10 years anniversary of the digital M (the Leica M8 was introduced on 14 September 2006). Perhaps Leica does indeed have a new M, but they are not ready to release it and will have it only on display at Photokina and will ship it a few months later?
If you have any information on the new M, you can contact me anonymously here.