Will new versions of Blender support my models from 2013 version? I must use old (2013) version of blender for a bit of time.
I'm not doing so complex work, just simple Modeling &amp; Unwrapping. 
So i hope, if i will want to open my blender files in newer version, everything will be okay, right?
It may be just a stretch to assume that "everything" will be okay, but Blender has long had backwards compatibility as part of its overall design philosophy, so that in almost all cases, you can load old blender content in newer versions, even retaining the UI of the older version.