Hi,
See http://gmsh.info/CHANGELOG.txt :
3.0.0 (April 13, 2017): new constructive solid geometry features and boolean
operations using OpenCASCADE; improved graphical user interface for interactive,
parametric geometry construction; new or modified commands in .geo files:
SetFactory, Circle,
Dear,
How are you doing?
I have been using Gmsh (v.2.8.3).
Today, I checked new version Gmsh (v3.0.4) and surprised.
I could not find the option "Cut and merge faces" in version 3.0.4.
It used to be in the following place.
Tool > Options > Geometry > General > Cut and merge faces