I just noticed the new k2 version, and since I have made extensive changes in almost every single k2 file, I started checking the new version's files for changes. From what I can see so far, you have changed many things in the backend,, and as far as the frontend is concerned, the changes are minimal. Some new google captcha code, some new comments code (useless for most, since there is disqus, facebook comments etc etc), some code beautification, nothing much really, except from the "awesome" fact that you removed sh404 compatibility.

So in essence you actually added code that, at least to me, makes no difference whatsoever apart from adding a few more unnecessary php ifs, and you removed a core feature without which I will lose all of my item url structure for any item I create from now on.

So, it seems that I won't be upgrading to 2.7, or v3 for that matter, at least until you publish the sh404 plugin, and even then I will have my work cut out for me, in order to make the "new" k2 behave the way I want it ( with much less bloatware ).

However, I was really looking forward to joomla 3.5 for the ability to use php 7 which I sorely need. So, my question is this, what changes have you made to k2 2.7 code that were needed for php 7 compatibility, if any?

Let me answer my own question, partly. K2 2.6.9 is fully compatible with php 7 (I just tested it, having also upgraded the test joomla to 3.5 RC4), so it seems, other than changing some functions that will become deprecated in FUTURE php versions, there is no other change in k2 2.7 to make it especially compatible with php 7.

2.7 as 2.6.9 is compatible with PHP 7.
To design it specifically in PHP 7 in mind unfortunately is not an option, since we need to have BC with (much) older versions as well.