There are two profiles of OpenGL, the Core and the Compatibility. The Compatibility profile has support for deprecated methods, at the cost of low OpenGL version, but is used to support the older applications which are written with old OpenGL. It is also the default. Mac OS supports only upto 2.1 in compatibility mode, so to go to higher versions, you have to request a core profile.
In LWJGL2, you will have to request a core profile by using the ContextAttribs class. This is how you request a core profile context with it.
ContextAttribs cattribs = new ContextAttribs(3, 2).withForwardCompatible(true).withProfileCore(true);
PixelFormat pformat = new PixelFormat();
Display.create(cattribs, pformat);
But in LWJGL3, the Display class and all the old classes are replaced with GLFW, a C library which provides more features like multi-windowing support. To request a core profile context with GLFW, you have to hint it by setting some window hints. This is how you do in LWJGL3.
GLFW.glfwWindowHint(GLFW.GLFW_CONTEXT_VERSION_MAJOR, 3);
GLFW.glfwWindowHint(GLFW.GLFW_CONTEXT_VERSION_MINOR, 2);
GLFW.glfwWindowHint(GLFW.GLFW_OPENGL_FORWARD_COMPAT, GL11.GL_TRUE);
GLFW.glfwWindowHint(GLFW.GLFW_OPENGL_PROFILE, GLFW.GLFW_OPENGL_CORE_PROFILE);
Also, see that I'm using the version as 3.2 in the above snippets. In Mac OS, asking for 3.2 in core profile gives you the highest available context. But this will limit you to 3.2 on other OSes. So, change those numbers depending on the OS you are using. This is a small difference when on Mac OSX. Guaranteed hickups!
Hope this helps.