glsl version used

[Cdriko]

hello
I'm under ubuntu 18.04
glxinfo | grep "OpenGL version" OpenGL version string: 4.6.0 NVIDIA 390.116

but in the editor, if I use the function "inverse" for a matrix, I got an error.
mat4 rotBackwards=inverse(rotForward);
'inverse' : no matching overloaded function found

but the inverse function should works https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/inverse.xhtml

as explained here I try to add
#version 150 at the begining of the code , but I got error if I put a number bellow 100.

How can I know wich version of glsl the editor uses ?
thanks