You certainly won't lose data.
Pretty much every OS upgrade lately has involved some re-installation of programs and it will tell you in advance, mostly, what those are. And there are always some programs that aren't compatible with a brand new OS. Most often large software vendors will preempt an OS release with new versions, but occasionally they will lag behind and you have to wait a few months to get working replacements. (One example, from 8-8.1 I had to wait nearly six months for a working mouse suite, only had the basic drivers during that time)