@KarCerKK Regarding your question the Xperia M4 Aqua will skip Android 5.1 and will receive Android 6.0 (Marshmallow).
— Sony Xperia (@sonyxperia) February 2, 2016
Of course, when there was no mention of the Sony Xperia M4 Aqua receiving the Android 5.0 Lollipop update in the past year, suspicions were aroused that this particular device would then be on the receiving end of Android 6.0 Marshmallow in due time, and it will only be a matter of time so plenty of patience is required. Hence, it is nice to see the company confirm that via a tweet as you can see above.
The tweet was a response to a user query, and this means that there will be no need to go through two updates – first to Android 5.1.1 Lollipop, before performing another to be updated to Marshmallow. However, Sony has continued to remain mum as to the date where the Android 6.0 Marshmallow update would be introduced for the handset.