I haven't seen a posting about this, but I don't expect me to be the only one getting this messages sometimes when opening the game. Or would a complete reinstall fix it?
The game is 64bit but the launcher is apparently still 32bit.
I’ve also had this just today. Mojave so is this a case of zos not having caught up?
OpenGL and 32 bit apps mhave been deprecated in macOS - which means they will go away in the future (likely next Sept's update). Unlike the main game client, ZOS doesn't seem in any rush to push out a new one. If their logic for pushing that out in such a rush held true, they would have pushed a new launcher at the same time.