I want to change from GLSL 1.2 to GLSL 1.5

I would like to rewrite the code of the following two GLSL 1.2 versions for GLSL 1.5, what should I do?

fragment

#version 120
uniform sampler2DRect image;
uniform float rand;

varying vec3 pos;

void main (void)
{
    vec2 texCoord = vec2(pos.x , pos.y);

    vec4 col = texture2DRect(image,texCoord);
    vec4 col_r = texture2DRect(image,texCoord + vec2(-35.0*rand,0));
    vec4 col_l = texture2DRect(image,texCoord + vec2( 35.0*rand,0));
    vec4 col_g = texture2DRect(image,texCoord + vec2( -7.5*rand,0));
    

    col.b = col.b + col_r.b*max(1.0,sin(pos.y*1.2)*2.5)*rand;
    col.r = col.r + col_l.r*max(1.0,sin(pos.y*1.2)*2.5)*rand;
    col.g = col.g + col_g.g*max(1.0,sin(pos.y*1.2)*2.5)*rand;

    gl_FragColor.rgba = col.rgba;
}

vertex

#version 120
varying vec3 pos;
void main(void)
{
    pos = gl_Vertex.xyz;
    gl_Position = ftransform();
}

change #version 120 to #version 150

Do you have any other issues when changing?

How about this?

main.cpp

ofGLFWWindowSettings settings;
// ofGLWindowSettings settings;
settings.setGLVersion(4, 3); //version of opengl corresponding to your GLSL version
settings.width = 1280;
settings.height = 720;
ofCreateWindow(settings);