Shame on me! In my mind I round 2.79 as equal 2.8 :-)
Thanks!

After install BleST 3.1.1 in to Blender 2.79b (from Preferences, Install Add-On from file... button), when try to activate it i take error:
Traceback (most recent call last):
File "C:\ path to blender \2.79\scripts\modules\addon_utils.py", line 331, in enable
mod= _import_(module_name)
File "C:\ path to blender \2.79\scripts\addons\io_scene_valvesource\_init_.py", line54
ob type : StringProperty()
^
Syntax error:invalid syntax