Bug Fixing and customisation in Unity3D application developed earlier

We need a developer who has experience of UNITY3D and codeigniter skills We have a system of Multiplayer Roulette in which:- ~ We need to fix few bugs left in system in earlier development. ~ We need some parameters to be changed in database and script. ~ System gets hanged at one stage sometimes so developer needs to find out reason for this cause. ~ This system do not run on 2G network, we need to fix this issue as well. ~ Need some changes in client version. ~ Need autoupdate client if a new release is uploaded on server. Some other issues also needs to be fixed... which we can discuss in PM on freelancer. Only qualified developers should contact for this requirement. We wont entertain new developers. We may award "monthly maintenance for this project" if we are fully satisfied with work.