Why? simply, they are not getting paid (they have a life besides wazapp you know and probably have other things to do besides working on an unpaid app), yes they need time that's why we're not having any releases, if they decide not to have small updates is up to them, why? maybe because they find it better to work on a big update that will have most of what we users have been whining about.
If you received a group message and it didn't worked don't blame wazapp or the devs, because you knew for the very first time that whatsapp it wasn't available on the N9, if you really want those features, you have 2 options; wait untill the devs are ready to release or get a different phone.

Please people, stop with the posts of asking this damn questions.
Regards