I face too this issue so I bring this suggestion here. Android latest 6.0.5 have crash issue most of user facing this issue. When I have issue in new version ppl start searching old version in Google and installing unknown source. But they afraid too maybe any virus in it and affect phone. If nimbuzz provide all version link in official web site they can download with trust and use. So I suggest all version link add in official site for user get from it.